U.S. flagAn official website of the United States government
                    Here's how you know **Official websites use .gov**
                            
                            A **.gov** website belongs to an official government organization in the United States.
 **Secure .gov websites use HTTPS**
                            
                            A **lock** (                            
                              A locked padlock                                                      
                            
                            ) or **https://** means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.


Menu Agricultural Research Service
						
                    U.S. DEPARTMENT OF AGRICULTURE
 Chemistry Research: Gainesville, FL
 close



    Research

                    Research Projects
                                    Publications
                                    Collaborations
                                    News
                People

                    Staff Listing
                                    CareersSearch small
                    Search
            
            ARS Home
                                About ARS
                                Contact Us




ARS Home Southeast Area Gainesville, Florida Center for Medical, Agricultural and Veterinary Entomology Chemistry Research Research Publications at this Location





- ARS National Programs
- Search for a scientific manuscript
- Search for a research project
- ARS Software
- Programs and Projects
- Collaborations
- Subjects of Investigation
- Publications

Title:   Author  item
                                            Vaughan, Marthaitem
                                            Huffaker, Alisaitem
                                            Schmelz, Ericitem
                                            CALLIS, KRISTINE - University Of Floridaitem
                                            Dafoe, Nicoleitem
                                            Allen Jr, Leonitem
                                            Teal, Peter
  Submitted to: Meeting Abstract
                                    Publication Type: Abstract Only
                                    Publication Acceptance Date: 6/7/2011
                                    Publication  Date: N/A
                                    Citation: N/AInterpretive Summary: Global climate change involves rising temperatures and potentially decreased rainfall or changes in rainfall patterns, which could dramatically decrease the yield of food crops. Drought alone can impair plant growth and development, but in nature plants are continuously exposed to both abiotic and biotic stresses. Fusarium verticillioides is an important fungal pathogen of Zea mays that causes seedling decay, stalk rot, ear rot, and produces carcinogenic mycotoxins, namely fumonisins. Consumption of fumonisins from contaminated food can cause serious illness that affect both humans and animals. Effects range from weight loss and reproductive abnormalities, to organ failure, cancer and death. Water stress, elevated temperatures and herbivore damage are ideal environmental conditions that promote F. verticilliodes growth and fumonisin production. Relatively little is known about the effects of climate change on Zea mays defense strategies against F. verticilliodes. In this study, we inoculated the stem of Zea mays var. Golden Queen with F. verticilliodes and measured the production of phytoalexins under normal (watered) and drought stress conditions.  At the site of F. verticilliodes inoculation a significant decrease in terpenoid phytoalexin production was detected in drought stressed plants as compared to those under normal conditions. Phytoalexin production is stimulated through the jasmomic acid (JA)- ethylene signaling pathway. JA production was suppressed in drought stressed plants infected with F. verticilliodes. One possible explanation for this suppression would be an increase in abscisic acid (ABA), a photohormone produced in response to water-deficit conditions.  ABA is thought to inhibit JA- ethylene dependent resistance. Although, we did not detect a significant increase of ABA in drought stressed plants inoculated with F. verticilliodes, ABA may have been elevated an earlier time point or before the addition of the fungal pathogen. The existence of an ABA-independent signal transduction cascade between the initial stress signal and the expression of drought- specific genes has previously been suggested and may also suppress JA-ethylene responses. Unlike the infected stem tissue, the control drought stressed roots had increased phytoalexin concentrations. This did not coincide with significantly elevated JA, however, the JA induction may have preceded the 48 hr time point.  Plants tolerate stress by activating signal transduction cascades that interact with each other in order to control and coordinate the physiological and biochemical responses necessary for adaptation and survival. Through these interacting signaling cascades plants may redirect defense metabolites to the tissue of most importance, which in the case of a drought stressed plant would be the roots. Our results suggest that the perception and response to abiotic stress may dictate or alter subsequent biotic stress responses.
                                Technical Abstract: Global climate change involves rising temperatures and potentially decreased rainfall or changes in rainfall patterns, which could dramatically decrease the yield of food crops. Drought alone can impair plant growth and development, but in nature plants are continuously exposed to both abiotic and biotic stresses. Fusarium verticillioides is an important fungal pathogen of Zea mays that causes seedling decay, stalk rot, ear rot, and produces carcinogenic mycotoxins, namely fumonisins. Consumption of fumonisins from contaminated food can cause serious illness that affect both humans and animals. Effects range from weight loss and reproductive abnormalities, to organ failure, cancer and death. Water stress, elevated temperatures and herbivore damage are ideal environmental conditions that promote F. verticilliodes growth and fumonisin production. Relatively little is known about the effects of climate change on Zea mays defense strategies against F. verticilliodes. In this study, we inoculated the stem of Zea mays var. Golden Queen with F. verticilliodes and measured the production of phytoalexins under normal (watered) and drought stress conditions.  At the site of F. verticilliodes inoculation a significant decrease in terpenoid phytoalexin production was detected in drought stressed plants as compared to those under normal conditions. Phytoalexin production is stimulated through the jasmomic acid (JA)- ethylene signaling pathway. JA production was suppressed in drought stressed plants infected with F. verticilliodes. One possible explanation for this suppression would be an increase in abscisic acid (ABA), a photohormone produced in response to water-deficit conditions.  ABA is thought to inhibit JA- ethylene dependent resistance. Although, we did not detect a significant increase of ABA in drought stressed plants inoculated with F. verticilliodes, ABA may have been elevated an earlier time point or before the addition of the fungal pathogen. The existence of an ABA-independent signal transduction cascade between the initial stress signal and the expression of drought- specific genes has previously been suggested and may also suppress JA-ethylene responses. Unlike the infected stem tissue, the control drought stressed roots had increased phytoalexin concentrations. This did not coincide with significantly elevated JA, however, the JA induction may have preceded the 48 hr time point.  Plants tolerate stress by activating signal transduction cascades that interact with each other in order to control and coordinate the physiological and biochemical responses necessary for adaptation and survival. Through these interacting signaling cascades plants may redirect defense metabolites to the tissue of most importance, which in the case of a drought stressed plant would be the roots. Our results suggest that the perception and response to abiotic stress may dictate or alter subsequent biotic stress responses.


Return to top


Connect with ARS Sign up


ARS Home
                            USDA.gov
                            Plain Writing
                            Policies & Links
                            Civil Rights Statements
                            FOIA
                            Accessibility Statement
                            Privacy Policy
                            Non-Discrimination Statement
                            Quality of Information
                            USA.gov
                            WhiteHouse.gov