# Autar K. Mattoo: Scientific Achievements

**Dynamics of Photosynthetic Reaction-Center Proteins**: Dr. Mattoo
conceived a novel concept of protein dynamics regulation by light using
a protein critical to photosynthesis. In 1996, he showed that
light-regulated D1 protein of the type-II reaction center of plastids is
a common target of environmental extremes (drought, high light and
ultraviolet (UV)-B irradiation). He showed that herbicides that inhibit
photosynthesis, such as diuron and atrazine, also inhibit degradation of
D1 by directly binding to it (1981, 1993). Dr. Mattoo\'s 1981
demonstration of the pivotal function of D1 in regulating photosynthetic
electron pathway as a type-II photosystem component became the basis for
its 1987 identification by scientists in Japan, United Kingdom and
Germany as the reaction center component of photosystem II. These
concepts have advanced scientific knowledge, opened new areas for
research worldwide and were recognized by a review in Cell and by News
and Views in Nature. These findings laid the foundation that scientists
worldwide have used in their research to understand how plants degrade
integral membrane proteins. Dr. Mattoo elucidated the complete metabolic
life history of this key component of the photosystem II and
demonstrated its modification by phosphate and fatty acids. His 1987
novel demonstrations of intra-membrane movement of proteins, and protein
acylation as a possible translocating signal are the first of their kind
in plant biology.

His 1993, 1997 discovery that light is a mediator in dephosphorylation
of chloroplast proteins is a novel finding in biology and has changed
the previous dogma that phosphatases are not regulated. Because
reversible protein phosphorylation offers a mechanism by which different
metabolic processes are regulated in response to internal and
environmental cues, these studies offer new avenues to modulate plant
growth and influence crop productivity. His research advanced knowledge
about environmental stress damage of plants and provided the identity
and nature of the target molecule for biotechnologists to select crop
plants for resistant germplasm and/or to create transgenic plants with
built-in defense mechanisms. His 1996 identification of UV-B radiation
target has direct implications in view of the anticipated depletion of
stratospheric ozone that could result in a marked increase in the
ambient levels of solar UV-B. In 1998, Dr.

Mattoo successfully applied an aspect of these basic fundamental
discoveries in developing (in collaboration with Italian scientists) an
ultrasensitive thermostable biosensor for rapid and sensitive detection
of residual herbicides such as atrazine and diuron in soil and water.
This photosystem II-based biosensor was patented in 2001. In 2002, Dr.
Mattoo demonstrated that light-dependent PSII reaction center D1 protein
phosphorylation is regulated by an endogenous circadian clock.

**Fruit Development and Regulation of Ethylene Biosynthesis**: Dr.
Mattoo laid enzymological foundation in fruit ripening with special
emphasis on the involvement of ethylene. An example is his first
demonstration in 1970 of citrate cleavage enzyme (ATP citrate lyase) in
plants and its role in ripening fruit in making available acetyl CoA and
oxaloacetate for anabolic processes. Thirty years later, molecular
genetics approaches have confirmed these early studies. Also, Dr. Mattoo
pioneered the regulatory interaction and metabolic linkage between two
antagonistic biochemical pathways in plants, which produce either
polyamines, growth promoters, and ethylene, a fruit ripening hormone. In
1981, he had discovered that polyamines inhibit ethylene biosynthesis in
a variety of fruit and vegetative tissues. Then, in 1992, he showed that
this happens by suppression of a key enzyme, called
1-aminocyclopropane-1-carboxylic acid (ACC) synthase, resulting in
rerouting the metabolic flux into synthetic reactions. He established
the concept that polyamines as growth substances regulate ethylene
production and delay fruit ripening, a physiological concept that is now
in textbooks; the 1991 book \"The Plant Hormone Ethylene\" refers to
this concept. His 1996 review on ethylene biosynthesis and perception is
widely quoted. He applied this new knowledge to produce transgenic
tomatoes transformed with a regulatable polyamine gene, providing a
novel strategy to genetically engineer crops for longer shelf-life and
value-added attributes, particularly functional foods. This led to a
number of international speaking engagements, including an address at
the BIO 2003 in the session: Functional Foods: Can you Get Too Much of a
Good Thing. Further, Dr. Mattoo\'s molecular inroads into the regulation
of senescence and fruit ripening processes led to new, first time
findings: in 2002, that ethylene signaling via the *etr*1 receptor is
responsible for delayed abscission and shorter internodes; in 1996,
identification of novel wound-regulated enzymes; in 1994, that the
function and conformation of the key enzyme in ethylene pathway is
regulated by part of its own structure; and in 1991, differential
regulation of genes in tomato fruit by slicing, ripening, ethylene and
light. In 2004, Dr. Mattoo's research provided first-ever scientific
basis for a linkage between the beneficial aspects of sustainable,
alternative agriculture systems and distinct activation of select genes
and proteins. His studies provided new dimensions, advanced scientific
knowledge and opened new research areas worldwide. These studies have
provided new ways to alter quality attributes of fruits and vegetables.

**Scientific Leadership**

Dr. Mattoo was instrumental in forging independent, highly visible,
international research teams. One team (Israel and Canada) was supported
by U.S./Israel Binational Agricultural Research and Development (BARD)
Fund grants from 1986 to 1992 and two (1990-93; 1991-94) USDA/National
Research Initiative (NRI) grants (total \$750, 000). An international
team (Italy and the Czech Republic), formed in 1996, was supported by a
North Atlantic Treaty Organization (NATO) grant (\$100,000). A third
collaborative effort (1995-2000) was scientific exchange and training,
supported by the Foreign Currency Research Program, U.S. Embassy in
India and Foreign Agricultural Service, Washington, D.C. Because of its
impact, the latter program was used as an example to set up a similar
exchange and training program with scientists in Bangladesh.

As an Adjunct Professor or graduate student advisor at several
universities, Dr. Mattoo has guided 29 Master of Science and 11 Doctoral
students. He has hosted/advised over 60 postdoctoral research associates
and visiting scientists/Professors from the United States and foreign
countries in biochemistry and molecular biology, some of whom are
directors, deans, vice presidents or professors at well recognized
institutions around the world. Dr. Mattoo has been a champion and
spokesperson in communicating to the public how the science of
biotechnology can improve world agriculture and solve world hunger. He
is sought out by other Agencies to explain in a layperson's language
basic science behind genomics and transgenic plants. For example in
October 2001, Senator Pimentel of the Phillippines specifically asked
the U.S. State Department to arrange a video conference for Dr. Mattoo
to make a presentation on Science and Trends in Biotechnology to members
of the Senate and U.S. Embassy in the Phillippines, which created an
excellent multiplier effect. In 2002 and then in 2004, Dr. Mattoo was
selected as the US Department of State International Speaker that led to
his extensive touring and lecturing on biotechnology to varied groups in
Philippines, Thailand, Malaysia and India, including an address to the
Philippines Congressional Staffers, the Senate of Philippines. In
September 2001, a video conference was arranged by the III Asia Pacific
Crop Protection Conference, New Delhi, India, for Dr. Mattoo to speak on
Biotechnology in Crop Protection. In addition, Dr. Mattoo has hosted
more than 100 delegations of scientists, scientific academies,
administrators, state ministers, congressional staff, State Department,
university teachers/students, journalists, etc., from over 30 countries
in the last 10 years, and been a spokesperson for the positive
implications of molecular biology and biotechnology.

In addition, Dr. Mattoo was a Special Member of Philippines Working
Group, Frontier Project on N2 fixation and N metabolism from 1995-97. He
served as USDA-ARS representative at several international workshops on
Plant Biotechnology and at Choice\'s Day, Michigan State University
(1995). Dr. Mattoo has been an invited reviewer for: 25 journals; grant
proposals for 12 granting offices; and promotion committees for
professors/ scientists at 12 national and international Universities or
Research Centers. He was a member of BARD Postdoctoral Fellowship
Selection Committee, U.S. Agency for International Development Review
Panels, Co-chair, ARS Plant Biotechnology Inventory & Assessment
Committee, and USDA-NRI Review Panels; member of the BARD Technical
Advisory Committee (1999-2002). He is currently a member of the Overseas
Scientific Advisory Committee in Biotechnology, Government of India.

All of Dr. Mattoo\'s achievements were recognized in 1999 when his
Research Personnel Evaluation System case writeup was reviewed by the
Supergrade Panel, who recommended him for Supergrade, ST/ES. This is a
unique honor which occurs rarely. Dr. Mattoo received in 1998 ARS
"Distinguished Scientist of the Year" award for outstanding scientific
and leadership achievement in plant biology, the highest honor in the
Agency. In 1999, he received USDA Secretary's Honor Award for scientific
excellence with the citation "major impact on world agriculture through
pioneering research contributions in plant biology".