Project description:Plants defend themselves against herbivores by activating a plethora of genetic and biochemical mechanisms aimed at reducing plant damage and insect survival. The short-term plant response to insect attack is well understood, but less is known about the maintenance of this response over time. We performed transcriptomic and metabolomics analyses in order to identify genes and metabolites involved in the long-term response of maize to attack by the corn borer Sesamina nonagrioides. To determine the role of elicitors present in caterpillar secretions, we also evaluated the response of maize stem challenged with insect regurgitates. The integrative analysis of the omics results revealed that the long-term response in maize is characterized by repression of the primary metabolism and a strong redox response, mainly mediated by germin-like proteins to produce anti-nutritive and toxic compounds that reduce insect viability, and with the glutathione–ascorbate cycle being crucial to minimize the adverse effects of reactive oxygen species (ROS) on the plant. Our results suggest that different defense mechanisms are involved in the long-term response compared to those reported during the early response. We also observed a marginal effect of the caterpillar regurgitates on the long-term defensive response.
Project description:We performed a transcriptomic analysis to identify genes differentially transcribed in the maize stem upon corn borer feeding and treatment with insects regurgitates by using the MACE (Massive Analysis of cDNA Ends) technology.
Project description:Stalk borers are major pests for some of the most important crops in the world, such as maize or rice. Plant defense mechanisms against these herbivores have been poorly investigated. The maize´s stalk responds to insect feeding activating defense genes including hormone biosynthetic-related or proteinase inhibitor transcripts. The most outstanding conclusion is that cells in the maize´s stalk undergo cell wall fortification after corn borer tunneling. We performed a gene expression profiling to identify those genes differentially expressed in maize after infestation with the corn borer S. nonagrioides.
Project description:Stalk borers are major pests for some of the most important crops in the world, such as maize or rice. Plant defense mechanisms against these herbivores have been poorly investigated. The maize´s stalk responds to insect feeding activating defense genes including hormone biosynthetic-related or proteinase inhibitor transcripts. The most outstanding conclusion is that cells in the maize´s stalk undergo cell wall fortification after corn borer tunneling. We performed a gene expression profiling to identify those genes differentially expressed in maize after infestation with the corn borer S. nonagrioides. Four genetically unrelated maize inbred lines (EP39, EP42, CM151 and PB130) were infested at VT (tasseling) developmental stage with a mass of approximately 40 eggs of S. nonagrioides laid on the sheath of the main ear. Another four biological replicates per genotype were used as control. Samples for RNA extraction were harvested fifteen days after infestation.
Project description:Jasmonic acid (JA) and methyl jasmonate (MeJA) regulate plant development, resistance to stress, and insect attack by inducing specific gene expression. However, little is known about the mechanism of plant defense against herbivore attack at a protein level. Using a high-resolution 2-DE gel, we identified 60 MeJA-responsive proteins and measured protein expression level changes. Among these 62 proteins, 43 proteins levels were increased while 11 proteins were decreased. We also found eight proteins uniquely expressed in response to MeJA treatment. The proteins identified in this study have important biological functions including photosynthesis and energy related proteins (38.4%), protein folding, degradation and regulated proteins (15.0%), stress and defense regulated proteins (11.7%), and redox-responsive proteins (8.3%). We found MeJA could not only induce plant defense mechanisms to insects, it also enhanced toxic protein production that potentially can be used for bio-control of Asian corn borer.
Project description:As a response to insect attack, maize (Zea mays) has inducible defenses that involve large changes in gene expression and metabolism. Piercing/sucking insects such as corn leaf aphids (Rhopalosiphum maidis) cause direct damage by acquiring phloem nutrients as well as indirect damage through the transmission of plant viruses. To elucidate the metabolic processes and gene expression changes involved in maize responses to aphid attack, leaves of inbred line B73 were infested with R. maidis for two to 96 hours.
Project description:Southern corn rust (SCR) is one of destructive diseases in maize caused by Puccinia polysora Undrew. (P. polysara), widely occurring in warm-temperate and tropical regions globally. To identify candidate SCR resistance-related proteins and understand the molecular mechanism underlaying the maize and P. polysara interaction, comparative proteomic analysis of susceptible and resistance maize lines was performed. A total of 6,612 proteins were successfully identified using an iTRAQ-based proteomic approach. Fold changes and statistical analysis demonstrated that 687 proteins increased and 802 proteins decreased in the resistant line, while 571 increased and 464 decreased in the susceptible line. One remorin protein, namely ZmREM1.3 (B4G1B0), was significantly induced by SCR in the resistant genotype, while decreased in susceptible genotype after P. polysara infection. Plant-specific remorin proteins have been shown to play important roles during microbial infection and plant signaling processes. Transgenic analysis showed that overexpression of ZmREM1.3 in maize confers enhanced resistance to the biotrophic fungal pathogen SCR. Upon pathogen challenge, the ZmREM1.3-overexpressing plants accumulated higher levels of defense hormones, SA and JA. Moreover, stronger induction of defense gene expression was also observed in ZmREM1.3-overexpressing maize plants in response to SCR infection. Taken together, our results support that ZmREM1.3 plays a positive role in regulating the maize defense against SCR likely through SA/JA-mediated defense signaling pathways. This is the first attempt for large scale analysis of the molecular mechanisms underlaying the maize and P. polysara interaction at the proteomic level, and the first evidence for remorin protein family in resistant to fungal disease.
Project description:Plants defend themselves against herbivores by activating a plethora of genetic and biochemical mechanisms aimed at reducing plant damage and insect survival. The short-term plant response to insect attack is well understood, but less is known about the maintenance of this response over time. We performed transcriptomic and metabolomics analyses in order to identify genes and metabolites involved in the long-term response of maize to attack by the corn borer Sesamina nonagrioides. To determine the role of elicitors present in caterpillar secretions, we also evaluated the response of maize stem challenged with insect regurgitates. The integrative analysis of the omics results revealed that the long-term response in maize is characterized by repression of the primary metabolism and a strong redox response, mainly mediated by germin-like proteins to produce anti-nutritive and toxic compounds that reduce insect viability, and with the glutathione–ascorbate cycle being crucial to minimize the adverse effects of reactive oxygen species (ROS) on the plant. Our results suggest that different defense mechanisms are involved in the long-term response compared to those reported during the early response. We also observed a marginal effect of the caterpillar regurgitates on the long-term defensive response.