<PAGE>   1
                                                                    EXHIBIT 4.15


                                WARRANT AGREEMENT

            This Warrant Agreement (the "Agreement"), dated as of January 14,
2000, between Large Scale Biology Corporation, formerly known as Biosource
Genetics Corporation, a California corporation (the "Company"), and Sebastian J.
Trusso (the "Warrantholder").

                                   RECITALS

            WHEREAS, the Company desires to issue to Warrantholder, 14,661
shares of the Company's Common Stock.

            NOW, THEREFORE, in consideration of the mutual covenants and
agreements contained herein, the Company and Warrantholder agree as follows:

                                  SECTION 1

                Representations and Warranties of the Company

            The Company hereby represents and warrants to the Warrantholder as
of January 29, 1988 as follows:

            1.1. Authorization. The Company has authorized the issuance to the
Warrantholder of Warrants to purchase shares of its Common Stock as provided
above in the form attached hereto. The Warrantholder shall also have the right
to require the Company to convert the Warrants, in whole but not in part, at any
time, or from time to time, prior to their expiration, into shares of Common
Stock as provided for in the Warrants.

            1.2. Organization and Standing; Articles and By-Laws. The Company is
a corporation duly organized and existing under, and by virtue of, the laws of
the State of California, and is in good standing under such laws. The Company
has the requisite corporate power to own and operate its properties and assets,
and to carry on its business as presently conducted and as proposed to be
conducted. The Company is qualified to do business as a foreign corporation in
each jurisdiction where the failure to be so qualified would have a material and
adverse effect on the Company. The Company has made available to the
Warrantholder copies of its Articles of Incorporation and By-Laws, as amended,
and minutes of Board and Shareholder meetings. Said copies are true, correct and
complete and contain all amendments through the date hereof.

            1.3. Corporate Power. The Company has all requisite legal and
corporate power to execute and deliver this Agreement, to issue the Warrants
hereunder, to issue the Common Stock issuable upon exercise of the Warrants, and
to carry out and perform its obligations under the terms of this Agreement.

            1.4. Subsidiaries.  The Company has no subsidiaries or affiliated
companies and does not otherwise own or control, directly or indirectly, any
other corporation, association or business entity.

<PAGE>   2
            1.5. Capitalization.

                  (a) The authorized capital of the Company consists of (i)
10,000,000 of Common Stock, of which 3,000,000 shares are issued and
outstanding, and (ii) 10,000,000 shares of Preferred Stock, of which 666,667
shares are issued and outstanding and are convertible into 666,667 shares of
Common Stock. All of such issued and outstanding shares have been duly
authorized and validly issued and are fully paid and nonassessable.

                  (b) The Company has reserved (i) 400,000 shares of Common
Stock for issuance under its Incentive Stock Option Plan, under which options to
purchase 0 shares of Common Stock are outstanding but unexercised. There are no
other options, warrants, conversion privileges or other rights presently
outstanding to purchase or otherwise acquire any authorized but unissued shares
of the Company's capital stock or other securities of the Company.

                  (c) Except as specified in the Series A Preferred Stock
Purchase Agreement dated as of September 25, 1987 between the Company and
certain of its investors, there are no preemptive rights to purchase new
issuances of the Company's capital stock. All outstanding shares of Common Stock
and Preferred Stock were issued in full compliance with all federal and state
securities laws.

            1.6. Financial Statements. The Company has delivered to the
Warrantholder its unaudited Consolidated Balance Sheet and Consolidated
Statement of Income at October 15, 1987 and for the 1-month period then ended
(the "Financial Statements"). The Financial Statements are complete and correct
in all material respects and have been prepared in accordance with generally
accepted accounting principles applied on a consistent basis throughout the
periods indicated. The Financial Statements accurately set out and describe the
financial condition and operating results of the Company as of the dates and
during the periods indicated therein, subject, as to the Consolidated Balance
Sheet and Consolidated Statement of Income at October 15, 1987, and for the
1-month period then ended, to normal year-end audit adjustments.

            1.7. Changes. Since October 15, 1987, there has not been any change
in the assets, liabilities, financial condition or operations of the Company
from that reflected in the Consolidated Balance Sheet at October 15, 1987,
referenced in subsection 1.6 above, except changes in the ordinary course of
business which have not been, individually or in the aggregate, materially
adverse.

            1.8. Material Liabilities. The Company has no material liabilities
or obligations, absolute or contingent (individually or in the aggregate),
except (a) the liabilities and obligations of the Company as set forth in the
Financial Statements, (b) liabilities and obligations which have occurred
subsequent to October 15, 1987, in the ordinary course of business, and which
have not been, either in any case or in the aggregate, materially adverse, and
(c) obligations under contracts incurred in the ordinary course of business,
which obligations are not required to be set forth on a Balance Sheet or in the
notes thereto in accordance with generally accepted accounting principles, and
which in any event are not materially adverse.


                                       2
<PAGE>   3
            1.9. Authorization. All corporate action on the part of the Company
and its directors and shareholders necessary for the authorization, execution,
delivery and performance of this Agreement by the Company, the authorization,
issuance and delivery of the Warrants (and Common Stock issuable upon exercise
of the Warrants), and the performance of the Company's obligations hereunder,
has been or will be taken. This Agreement, when executed and delivered by the
Company, shall constitute a valid and binding obligation of the Company
enforceable in accordance with its terms, subject to laws of general application
relating to bankruptcy, insolvency and the relief of debtors and rules of law
governing specific performance, injunctive relief or other equitable remedies.
The Warrants, when issued in compliance with the provisions of this Agreement,
will be validly issued, fully paid and nonassessable and will be free of any
liens and encumbrances. The Common Stock issuable upon exercise of the Warrants
has been duly and validly reserved and, when issued in compliance with the
provisions of this Agreement, will be validly issued, fully paid and
nonassessable, and will be free of any liens or encumbrances; provided, however,
that the Warrants (and Common Stock issuable upon exercise of the Warrants) may
be subject to restrictions on transfer under state and/or federal securities
laws as set forth herein.

            1.10. Title to Properties and Assets: Liens, etc. The Company has
good and marketable title to its properties and assets, and has good title to
all its leasehold interests, in each case subject to no mortgage, pledge, lien,
lease encumbrance or charge, other than (a) the lien of current taxes not yet
due and payable, and (b) possible liens, charges and encumbrances which do not
in any case materially detract from the value of the property subject thereto or
materially impair the operations of the Company.

            1.11. Patents, Trademarks, etc. To the best of the Company's
knowledge, the Company owns, possesses, has access to, or can become licensed on
reasonable terms under, all patents, patent applications, trademarks, trade
names, inventions, franchises, licenses, permits, computer software and
copyrights necessary for the operation of its business as now conducted, with no
known infringement of, or conflict with, the rights of others.

            1.12. Compliance with Other Instruments. The Company is not in
violation of any term of its Articles of Incorporation or By-Laws, as amended,
or in violation of any material agreement, instrument, judgment, decree or, to
the best of its knowledge, any material order, statute, rule or regulation
applicable to the Company. The execution, delivery and performance of this
Agreement, and the consummation of the transactions contemplated herein will not
result in any such violation or be in conflict with, or constitute a default
under any such provision or agreement, and will not accelerate the performance
provided by the terms of any material agreement or instrument to which the
Company is a party, or constitute a default thereunder, or an event which, with
the lapse of time or action by a third party, could result in a default
thereunder, or result in the creation of any lien, charge or encumbrance upon
any assets or properties of the Company, which breach, default, lien, charge or
encumbrance, singularly or in the aggregate, would materially and adversely
affect the business or property of the Company.

            1.13. Litigation, etc. There are no actions, suits, proceedings or
governmental or regulatory agency investigations pending against the Company or
its properties before any court or governmental agency (nor, to the best of the
Company's knowledge, is there any basis therefor or written threat thereof),
which, either in any case or in the aggregate, might result in


                                       3
<PAGE>   4
any material adverse change in the business or financial condition of the
Company or any of its properties or assets, or in any material impairment of the
right or ability of the Company to carry on its business as now conducted or as
proposed to be conducted, or in any material liability on the part of the
Company, and none which questions the validity of this Agreement or any action
taken or to be taken in connection herewith.

            1.14. Employees. To the best of the Company's knowledge, no employee
of the Company is in violation of any material term of any employment contract,
patent disclosure agreement or any other contract or agreement relating to the
relationship of any such employee with the Company or any prior employer because
of the nature of the business conducted by the Company.

            1.15. Insurance. The Company has in full force and effect insurance
policies, with extended coverage, insuring the Company and its property and
business against such losses and risks, and in such amounts, as are customary
for corporations engaged in a similar business and similarly situated.

            1.16. Governmental Consent, etc. No consent, approval or
authorization of, or designation, declaration or filing with any governmental
authority on the part of the Company is required in connection with the valid
execution and delivery of this Agreement or the issuance of the Warrants (and
Common Stock issuable upon exercise of the Warrants) or the consummation of any
other transaction contemplated hereby, except for the filing of notices pursuant
to Regulation D under the 1933 Act and Section 25102(f) of the California
Corporate Securities Law, which filings will be effective by the time required
thereby.

            1.17. Offering. Subject to the accuracy of the Warrantholder's
representations in Section 2 hereof, and in written responses to the Company's
inquiries, the issuance of the Warrants (and Common Stock issuable upon exercise
of the Warrants) will constitute transactions exempt from (i) the registration
requirements of Section 5 of the 1933 Act, in reliance upon Section 4(2)
thereof, and (ii) the qualification requirements of the California Corporate
Securities Law, in reliance upon Section 25102(f) thereof.

            1.18. Material Contracts and Commitments. All material contracts,
agreements and instruments to which the Company is a party are in full force and
effect in all material respects, and are valid, binding and enforceable by the
Company in accordance with their respective terms, subject to the effect of
applicable bankruptcy and other similar laws affecting the rights of creditors
generally, and rules of laws concerning equitable remedies.

            1.19. Brokers or Finders. The Company has not incurred, and will not
incur, directly or indirectly, any liability for brokerage or finders' fees or
agents' commissions or any similar charges in connection with this Agreement or
any transaction contemplated hereby.

            1.20. Disclosure. No representation or warranty of the Company
contained in this Agreement and any certificate or exhibit furnished or to be
furnished to the Warrantholder pursuant hereto or in connection with the
transactions contemplated hereby (when read together) contains any untrue
statement of a material fact or omits to state a material fact necessary in


                                       4
<PAGE>   5
order to make the statements contained therein, in light of the circumstances
under which they were made, not misleading.

            1.21. Manufacturing Rights.  The Company has not granted rights
to manufacture or assemble its products to any other entity.

            1.22. Transactions with Principals. With the exception of minor
indebtedness incurred in the ordinary course of business, the Company is not
indebted to any employee, shareholder, officer or director of the Company, and
no such employee, shareholder, officer or director is indebted to the Company.

                                    SECTION 2

                      Representations of the Warrantholder

            2.1. Investment Representations.  This Agreement has been entered
by the Company in reliance upon the following representations of the
Warrantholder, which by its execution hereof the Warrantholder hereby
confirms:

                  (a) The Warrants (and Common Stock issuable upon exercise of
the Warrants) will be acquired for investment and not with a view to the sale or
distribution of any part thereof. Except as specified in this subsection 2.1(a),
the Warrantholder has no present intention of selling, granting participations
in or otherwise distributing the same, but subject nevertheless to any
requirement of law that the disposition of its property shall at all times be
within its control. By executing this Agreement, the Warrantholder further
represents that, with the exception of an arrangement to transfer the Warrants
to not more than three partnerships, the general partner of which is the sole
shareholder of the Warrantholder, the Warrantholder does not have any contract,
undertaking, agreement or arrangement with any person to sell, transfer or grant
participations to any third person, with respect to any of the Warrants (or
Common Stock issuable upon exercise of the Warrants).

                  (b) The Warrantholder understands (i) that the Warrants (and
Common Stock issuable upon exercise of the Warrants) are not registered under
the 1933 Act or qualified under applicable state securities laws on the ground
that the issuance contemplated by this Agreement will be exempt from the
registration and qualification requirements thereof, and (ii) that the Company's
reliance on such exemption is predicated on the Warrantholder's representations
set forth herein.

                  (c) Except in the event of a transfer to an entity or
entities, the general partner of which is the sole shareholder of the
Warrantholder, in no event will it make a disposition of the Warrants issuable
hereunder (or Common Stock issuable upon exercise of the Warrants) unless and
until (i) it shall have notified the Company of the proposed disposition and
shall have furnished the Company with a statement of the circumstances
surrounding the proposed disposition, and (ii) if requested by the Company, it
shall have furnished the Company with an opinion of counsel satisfactory to the
Company and its counsel to the effect that (A) appropriate action necessary for
compliance with the 1933 Act has been taken, or (B) an exemption from the
registration requirements of the 1933 Act is available.


                                       5
<PAGE>   6
                  (d) The Warrantholder is able to fend for itself in the
transactions contemplated by this Agreement, has such knowledge and experience
in financial and business matters as to be capable of evaluating the merits and
risks of its investment, has the ability to bear the economic risks of its
investment, and has had all questions which it has asked answered by the
Company.

                  (e) The Warrantholder understands that if the Company does not
register with the Securities and Exchange Commission pursuant to Section 12, or
file reports pursuant to Section 15(d), of the Securities Exchange Act of 1934
(the "1934 Act"), or if a registration statement covering the securities (or
filing pursuant to the exemption from registration under Regulation A of the
1933 Act) under the 1933 Act is not in effect when it desires to sell the
Warrants (or Common Stock issuable upon exercise of the Warrants), it may be
required to hold such securities for an indefinite period. The Warrantholder
also acknowledges that it understands that any sale of the Warrants (or Common
Stock issuable upon exercise of the Warrants) which might be made by it in
reliance upon Rule 144 under the 1933 Act may be made only in limited amounts in
accordance with the terms and conditions of that Rule.

            2.2. Legends; Stop-Transfer Orders.

                  (a) All certificates for the Warrants (and Common Stock
issuable upon exercise of the Warrants) may bear legends in substantially the
following forms:

      THE SECURITIES REPRESENTED HEREBY HAVE NOT BEEN REGISTERED UNDER THE
      SECURITIES ACT OF 1933, AS AMENDED, AND ACCORDINGLY, MAY BE TRANSFERRED
      ONLY IN A TRANSACTION WHICH IS REGISTERED UNDER SUCH ACT OR IS EXEMPT FROM
      SUCH REGISTRATION REQUIREMENT.

      THE SECURITIES REPRESENTED HEREBY ARE SUBJECT TO THAT CERTAIN WARRANT
      AGREEMENT DATED JANUARY 29, 1988, A COPY OF WHICH CAN BE OBTAINED UPON
      REQUEST FROM THE SECRETARY OF THE CORPORATION AT ITS PRINCIPAL OFFICES.

                  (b) The certificates for the Warrants (and Common Stock
issuable upon exercise of the Warrants) may also bear any legend required by
any applicable state blue sky law.

                  (c) The Company may impose stop-transfer instructions with
respect to the provisions of Sections 2.1(c) and 2.2(a) hereof.

                                    SECTION 3

                               Registration Rights

            The Company hereby covenants and agrees as follows:


                                       6
<PAGE>   7
            3.1. Certain Definitions. For the purposes of this Section 3, the
following terms shall have the following meanings:

                  (a) "Registrable Securities" shall mean (i) the Warrants and
(ii) the shares of Common Stock issued or issuable upon exercise or conversion
of the Warrants.

                  (b) "1933 Act" shall mean the Securities Act of 1933, as
amended.

                  (c) "1934 Act" shall mean the Securities Exchange Act of
1934, as amended.

            3.2. Requests for Registration.

                  (a) After the Company becomes eligible for registration of its
Common Stock on Form S-3 under the 1933 Act (or such successor form as may be
approved by the Securities and Exchange Commission) in a Secondary Offering (as
that term is defined in the "Eligibility Requirements for Use of Form S-3"), the
Warrantholder may request that the Company file a registration statement on Form
S-3 for a public offering covering Registrable Securities. Upon receipt of such
request, the Company shall promptly use its best efforts to cause such
Registrable Securities to be registered on such form and qualified in such
jurisdictions as the Warrantholder may reasonably request, and to cause such
registration and qualifications to remain effective until the sale of all of the
Registrable Securities included in the registration statement, or ninety days
after the effective date thereof, whichever first occurs.

                  (b) If, at the time of the Warrantholder's request under
subsection 3.2(a), the Company has publicly announced its intention to register
any of its securities for a public offering under the 1933 Act, no registration
of Registrable Securities shall be initiated under this subsection 3.2(b) until
90 days after the effective date of such registration, unless the Company is no
longer proceeding diligently to effect such registration, whether such
registration is for the sale of securities for the Company's account or for the
account of others. If the Company shall furnish to the Warrantholder a
certificate signed by the President of the Company stating that, in the good
faith judgment of the Board of Directors of the Company, it would be seriously
detrimental to the Company and its shareholders for such registration statement
to be filed at the time of the Warrantholder's request, and it is therefore
essential to defer the filing of such registration statement, the Company shall
have the right to defer such filing for a period of not more than 60 days after
receipt of the request of the Warrantholder. Notwithstanding anything to the
contrary contained in this Agreement or in the Warrants, (i) the Company may not
utilize its rights to delay a registration statement under this subsection
3.2(b) more than once in any twelve-month period, and (ii) the Warrants shall
not expire until at least 90 days after the effective date of a registration
timely requested under subsection 3.2(a).

            3.3. Incidental Registration.

            (a) Whenever the Company proposes to register any of its Common
Stock under the 1933 Act for a public offering for cash, whether as a primary or
secondary offering or pursuant to registration rights granted to holders of
other securities of the Company (other than a registration relating to employee
benefit plans), the Company shall, each such time, give the Warrantholder 45
days advance written notice thereof. Upon the written request of the


                                       7
<PAGE>   8
Warrantholder within 30 days after the Warrantholder's receipt of such notice,
the Company shall use its best efforts to cause to be included in such
registration all of the Registrable Securities which the Warrantholder requests
to be registered; provided, however, that the Warrantholder agrees to sell such
Registrable Securities in the same manner and on the same terms and conditions
as the other Common Stock which the Company proposes to register.

                  (b) Notwithstanding anything to the contrary contained in
subsection 3.3(a), if the registration for which notice is given under
subsection 3.3(a) will include Common Stock to be sold in an underwritten public
offering, and if the managing underwriter advises the Company that, in its good
faith judgment, the inclusion of the Warrantholder's Registrable Securities
would adversely affect the price that the Company would otherwise receive for
its Common Stock, the managing underwriter may exclude some or all of the
Warrantholder's Registrable Securities; provided however, (i) in no event shall
the number of the Warrantholder's Registrable Securities included in the
underwriting be less than the result obtained by dividing (A) the product of (1)
the number of Registrable Securities requested by the Warrantholder to be
included in the offering multiplied by (2) the number of shares of Common Stock
actually included in the offering, by (B) the number of shares of Common Stock
requested to be included in the offering by all holders thereof plus the number
of shares of Common Stock included therein for the account of the Company; and
(ii) any of the Warrantholder's Registrable Securities excluded from the
offering shall, if the Warrantholder so requests, be included in the Common
Stock covered by such registration statement, but not in the shares to be
underwritten, in which case the Warrantholder will be required to agree not to
seek to offer or sell any of its Registrable Securities for a period of 90 days
or such greater period not in excess of 180 days that the managing underwriter
may request after the initial effective date of the registration statement for
the underwritten offering. Further, the Warrantholder will be required to
comply, to the reasonable satisfaction of counsel to the Company, with any other
requirements applicable to "shelf" registrations, whether under Rule 415 under
the 1933 Act or otherwise.

            3.4. Obligations of the Company. Whenever required under subsection
3.2 or 3.3 to use its best efforts to effect the registration of any of the
Registrable Securities, the Company shall, as expeditiously as possible:

                  (a) Prepare and file with the Securities and Exchange
Commission a registration statement with respect to such Registrable Securities
and use its best efforts to cause such registration statement to become and
remain effective; provided, however, that in connection with any proposed
registration intended to permit an offering of any securities from time to time
(i.e., a so-called "shelf registration"), the Company shall in no event be
obligated to keep such registration statement effective for more than one year;

                  (b) Prepare and file with the Securities and Exchange
Commission such amendments and supplements to such registration statement and
the prospectus used in connection therewith as may be necessary to comply with
the provisions of the 1933 Act with respect to the disposition of all securities
covered by such registration statement;

                  (c) Furnish to the Warrantholder such number of copies of a
prospectus, including a preliminary prospectus, in conformity with the
requirements of the 1933


                                       8
<PAGE>   9
Act, and such other documents as the Warrantholder may reasonably request in
order to facilitate the disposition of Registrable Securities owned by it; and

                  (d) Use its best efforts to register and qualify the
securities covered by such registration statement under such other securities or
Blue Sky laws of such jurisdictions as shall be reasonably appropriate for the
distribution of the securities covered by the registration statement, provided
that the Company shall not be required in connection therewith or as a condition
thereto to qualify to do business or to file a general consent to service of
process in any such states or jurisdictions.

            3.5. Furnish Information. It shall be a condition precedent to the
obligations of the Company to take any action pursuant to this Section 3 that
the Warrantholder shall furnish to the Company such information regarding it,
the Registrable Securities held by it and the intended method of disposition
thereof as the Company shall reasonably request and as shall be required in
connection with the action to be taken by the Company.

            3.6. Expenses of Registration. All expenses incurred in connection
with a registration pursuant to subsection 3.2 and 3.3 (excluding underwriting
commissions and discounts), including without limitation all registration and
qualification fees, printing and accounting fees and fees and disbursements of
counsel for the Company and of counsel to the Warrantholder not in excess of
$5,000 shall be borne by the Company; provided, however, that the Company shall
not be required to pay for any expenses incurred by the Company under subsection
3.2 if the registration statement is withdrawn at the request of the
Warrantholder for reasons other than events materially and adversely affecting
the Company subsequent to the filing, and not contemplated at the time of
filing, of the registration statement, unless the Warrantholder shall agree to
forfeit its right to one demand registration pursuant to subsection 3.2.

            3.7. Underwriting Requirements.

                  (a) If the Warrantholder intends to distribute the Registrable
Securities covered by its request by means of an underwriting, it shall so
advise the Company as a part of its request made pursuant to subsection 3.2. The
Company shall enter into an underwriting agreement in customary form with the
representative of the underwriter or underwriters selected for such underwriting
by the Warrantholder.

                  (b) In connection with any underwritten public offering in
which the Warrantholder has a right to participate under subsections 3.2 or 3.3
hereof, and subject to the agreement of the underwriters, the Warrantholder may
sell to the underwriters, in lieu of all or any part of the shares of Common
Stock to be included by the Warrantholder in the offering, Warrants to purchase
such shares of Common Stock.

            3.8. Delay of Registration. So long as the Company has given any
notice required by subsection 3.3 hereof, the Warrantholder shall not have any
right to take any action to restrain, enjoin or otherwise delay any registration
as the result of any controversy which might arise with respect to the
interpretation or implementation of this Section 3; but nothing in


                                       9
<PAGE>   10
this subsection 3.8 shall be construed as limiting the Warrantholder's right to
damages for breach of this Agreement.

            3.9. Indemnification. In the event any of the Registrable Securities
are included in a registration statement under this Section 3:

                  (a) To the extent permitted by law, the Company will indemnify
and hold harmless the Warrantholder, each officer, director or partner of the
Warrantholder, any underwriter (as defined in the 1933 Act) for the
Warrantholder, and each person, if any, who controls the Warrantholder, or such
underwriter with the meaning of the 1933 Act, against any losses, claims,
damages or liabilities, joint or several, to which they may become subject
under the 1933 Act, or otherwise, insofar as such losses, claims, damages or
liabilities (or actions in respect thereof) arise out of or are based upon any
untrue or alleged untrue statement of any material fact contained in such
registration statement, including any preliminary prospectus or final prospectus
contained therein or any amendments or supplements thereto, or arise out of or
are based upon the omission or alleged omission to state therein a material fact
required to be stated therein, or necessary to make the statements therein not
misleading; and will reimburse the Warrantholder, each such officer, director or
partner of the Warrantholder, and such underwriter or controlling person for any
legal or other expenses reasonably incurred by them in connection with
investigating or defending any such loss, claim, damage, liability or action;
provided, however, that the indemnity agreement contained in this subsection
3.9(a) shall not apply to amounts paid in settlement of any such loss, claim,
damage, liability or action if such settlement is effected without the consent
of the Company (which consent shall not be unreasonably withheld) nor shall the
Company be liable in any such case for any such loss, claim, damage liability or
action to the extent that it arises out of or is based upon an untrue statement
or alleged untrue statement or omission or alleged omission made in connection
with such registration statement, preliminary prospectus, final prospectus, or
amendments or supplements thereto, in reliance upon and in conformity with
written information furnished expressly for use in connection with such
registration by the Warrantholder or any such underwriter or controlling person.

                  (b) To the extent permitted by law, the Warrantholder will
indemnify and hold harmless the Company, each of its directors, each of its
officers who have signed such registration statement, each person, if any, who
controls the Company within the meaning of the 1933 Act and any underwriter for
the Company (within the meaning of the 1933 Act) against any losses, claims,
damages or liabilities to which the Company or any such director, officer,
controlling person or underwriter may become subject, under the 1933 Act or
otherwise, insofar as such losses, claims, damages or liabilities (or actions in
respect thereto) arise out of or are based upon any untrue or alleged untrue
statement of any material fact contained in such registration statement,
including any preliminary prospectus or final prospectus contained therein or
any amendments or supplements thereto, or arise out of or based upon the
omission or alleged omission to state therein a material fact required to be
stated therein or necessary to make the statements therein not misleading, in
each case to the extent, but only to the extent, that such untrue statement or
alleged untrue statement or omission or alleged omission was made in such
registration statement, preliminary prospectus, final prospectus, or amendments
or supplements thereto, in reliance upon and in conformity with written
information furnished by the Warrantholder expressly for use in connection with
such registration; and the Warrantholder will


                                       10
<PAGE>   11
reimburse any legal or other expenses reasonably incurred by the Company or any
such director, officer, controlling person or underwriter in connection with
investigating or defending any such loss, claim, damage, liability or action;
provided, however, that the liability of the Warrantholder under this subsection
3.9 shall be limited to the amount of proceeds received by the Warrantholder
from the sale of the Warrant or the Common Stock issued upon exercise of the
Warrant. It is agreed that the indemnity agreement contained in this subsection
3.9(b) shall not apply to amounts paid in settlement of any such loss, claim,
damage, liability or action if such settlement is effected without the consent
of the Warrantholder (which consent shall not be unreasonably withheld).

                  (c) Promptly after receipt by a party indemnified under this
subsection 3.9 of notice of commencement of any action, such indemnified party
will, if a claim in respect thereof is to be made against any indemnifying party
under this subsection 3.9, notify the indemnifying party in writing of the
commencement thereof and the indemnifying party shall have the right to
participate in, and, to the extent the indemnifying party desires, jointly

                  (d) with any other indemnifying party similarly noticed, to
assume the defense thereof with counsel mutually satisfactory to the parties.
The failure to notify an indemnifying party promptly of the commencement of any
such action, if prejudicial to his ability to defend such action, shall relieve
such indemnifying party of any liability to the indemnified party under this
subsection 3.9, but the omission so to notify the indemnifying party will not
relieve him of any liability which he may have to any indemnified party other
than under this subsection 3.9.

            3.10. Transfer of Registration Rights. The registration rights of
the Warrantholder under this Section 3 may be transferred to any transferee of
the Warrantholder who acquires Warrants to purchase at least 1,000 shares of the
Company's outstanding Common Stock; provided that the Company is given written
notice by the Warrantholder at the time of such transfer stating the name and
address of the transferee and identifying the Registrable Securities with
respect to which the rights under this Section 3 are being assigned and,
provided further, that there shall be no such restriction on distribution of
said registration rights to any entity of which the general partner is the sole
shareholder of the Warrantholder.

            3.11. Reporting Requirements. With a view toward making available
the benefits of certain rules and regulations of the Securities and Exchange
Commission that may at any time permit the sale of the Common Stock issuable
upon exercise of the Warrants to the public with or without registration, from
and after the effective date of the Company's initial registration statement
under the 1933 Act, the Company agrees to:

                  (a) Timely file and keep available such information, documents
and reports as may be required or prescribed by the Securities and Exchange
Commission under Section 13 or 15(d) (whichever is applicable) of the 1934 Act
as well as any other information, reports and documents required of the Company
under the 1933 Act or 1934 Act;

                  (b) Prepare and file with the Securities and Exchange
Commission as soon as possible, a registration statement under Section 12 of the
1934 Act, regardless of whether the Company is then otherwise required to do so;


                                       11
<PAGE>   12
                  (c) Use its best efforts to qualify for the use of Form S-3 to
register its Common Stock in Secondary Offerings (as that term is defined in the
"Eligibility Requirements for Use of Form S-3"); and

                  (d) Furnish to the Warrantholder or any of its transferees,
forthwith upon request, a written statement by the Company as to its compliance
with the reporting requirements of Rule 144, the "Eligibility Requirements for
Use of Form S-3," the 1933 Act and the 1934 Act, as well as a copy of the most
recent annual or quarterly report of the Company and such other reports and
documents of the Company as the Warrantholder or any of its transferees may
reasonably request in availing itself of any rule or regulation of the
Securities and Exchange Commission allowing the Warrantholder or any of its
transferees to sell such securities with or without registration.

            3.12. Registration Rights. Except as set forth or referred to in
this Agreement and in the Series C Preferred Stock Purchase Agreement dated as
of June 27, 1986 between the Company and certain of its investors, the Company
is not under any obligation to register under the Securities Act of 1933, as
amended (the "1933 Act"), any of its presently outstanding securities or any of
its securities which may hereafter be issued.

                                    SECTION 4

                            Covenants of the Company

            4.1. Financial Statements. The Company shall deliver to the
Warrantholder (i) within 120 days after the end of the fiscal year of the
Company, a consolidated statement of income for such fiscal year, a consolidated
balance sheet of the Company as of the end of such year and a consolidated
statement of the sources and application of funds for such year, which year-end
financial reports shall be in reasonable detail and certified by independent
public accountants of nationally recognized standing selected by the Company,
and (ii) within 45 days after the end of each fiscal quarter other than the last
fiscal quarter, unaudited consolidated statements of income and sources and
application of funds for such quarter and a consolidated balance sheet as of the
end of such quarter.

                                    SECTION 5

                                  Miscellaneous

            5.1. Agreement Is Entire Contract. This Agreement and the Warrant
attached hereto constitute the entire contract between the parties hereto with
respect to the Warrants, and no party shall be liable or bound to the other in
any manner by any warranties, representations or covenants except as
specifically set forth herein. The terms and conditions of this Agreement shall
inure to the benefit of and be binding upon the respective successors and,
permitted assigns of the parties hereto. Nothing in this Agreement, express or
implied, is intended to confer upon any party, other than the parties hereto,
and their respective successors and permitted assigns, any rights, remedies,
obligations or liabilities under or by reason of this Agreement, except as
expressly provided herein.


                                       12
<PAGE>   13
            5.2. Governing Law. This Agreement shall be governed by and
construed under the laws of the State of California.

            5.3. Counterparts. This Agreement may be executed in two or more
counterparts, each of which shall be deemed an original, but all of which
together shall constitute one and the same instrument.

            5.4. Titles and Subtitles.  The titles of the paragraphs and
subparagraphs of this Agreement are for convenience and are not to be
considered in construing this Agreement.

            5.5. Notices. Any notice required or permitted hereunder shall be
given in writing and shall be deemed effectively given upon personal delivery or
upon deposit in the United States mail, by registered or certified mail,
addressed to (i) the Warrantholder at P.O. Box 2470, 7677 Oakport Street,
Oakland, California, 94614 and (ii) the Company at 3333 Vaca Valley Parkway,
Ste. 1000, Vacaville, California 95688, or at such other address as any such
party may designate by ten days written notice to the other party.

            5.6. Finder's Fees. Each party hereto represents that it is not and
will not and will not be obligated for any finder's fee or commission in
connection with this transaction. The Warrantholder hereby agrees to indemnify
and to hold harmless the Company from any liability for any commission or
compensation in the nature of a finder's fee (and the costs and expenses of
defending against such liability or asserted liability) for which the
Warrantholder or any of its respective employees or representatives is
responsible. The Company agrees to indemnify and hold harmless the Warrantholder
from any liability for any commission or compensation in the nature of a
finder's fee (and the cost and expenses of defending against such liability or
asserted liability) for which the Company or any of its officers, employees or
representatives is responsible.

            5.7. Specific Performance. The parties hereto agree that in the
event of a breach of any of the provisions hereof equitable remedies and the
remedy of specific performance, among others, shall be appropriate remedies.

            5.8. Survival of Warranties. The warranties and representations of
the Company contained in or made pursuant to this Agreement shall survive the
execution and delivery of this Agreement and the closing date hereunder.

            5.9. Severability. If one or more provisions of this Agreement are
held to be unenforceable under applicable law, such provision shall be severed
from this Agreement as if such provision were not included and the balance of
this Agreement shall be enforceable in accordance with its terms.

            5.10. Amendment of Agreement. Any provision of this Agreement may be
amended by a written instrument signed by the Company and by the Warrantholder
and/or subsequent holders of a majority of the Warrants (and Common Stock
issuable upon exercise of the Warrants).


                                       13
<PAGE>   14

            IN WITNESS WHEREOF, the parties hereto have executed this Agreement
as of the date first above written.

                             Company: LARGE SCALE BIOLOGY CORPORATION

                             By:  /s/ Robert L. Erwin
                                  ----------------------------------------------
                             Its: Chairman of the Board
                                  ----------------------------------------------

                             Warrantholder: Sebastian J. Trusso

                             By: /s/ Sebastian J. Trusso
                                  ----------------------------------------------


                                       14