Insights into the role of SUMO in regulating drought stress responses in pigeonpea (Cajanus cajan).

KEY MESSAGE: We have identified and analyzed 28 SUMO-pathway proteins from pigeonpea. Enhanced transcripts of pathway genes and increased SUMO conjugation under drought signifies the role of SUMO in regulating stress. Being a protein-rich and nutrient-dense legume crop, pigeonpea (Cajanus cajan) holds a vital position in a vegetarian meal. It is a resilient crop capable of striving in harsh climates and provides a means of subsistence to small-holding farmers. Nevertheless, extremes of water scarcity and drought conditions, especially during seedling and reproductive stages, remains a major issue severely impacting the growth and overall productivity of pigeonpea. Small ubiquitin-like modifier (SUMO), a post-translational modification system, plays a pivotal role in fortifying plants against stressful conditions by rapid reprogramming of molecular events. In this study, we have scanned the entire pigeonpea genome and identified 28 candidates corresponding to SUMO machinery components of pigeonpea. qRT-PCR analysis of different SUMO machinery genes validated their presence under natural conditions. The analysis of the promoters of identified SUMO machinery genes revealed the presence of abiotic stress-related cis-regulatory elements highlighting the potential involvement of the genes in abiotic stress responses. The transcript level analysis of selected SUMO machinery genes and global SUMO status of pigeonpea proteins in response to drought stress suggests an integral role of SUMO in regulating drought stress conditions in pigeonpea. Collectively, the work puts forward a detailed in silico analysis of pigeonpea SUMO machinery candidates and highlights the essential role of SUMOylation in drought stress responses. Being the first report on a pulse crop, the study will serve as a resource for devising strategies for counteracting drought stress in pigeonpea that can be further extended to other pulse crops.

Engineering the AEG1 promoter from cotton to develop male sterile lines.

KEYMESSAGE: A promoter expressing in anther and roots is made anther specific. The modified promoter is used to drive barnase gene and develop male sterile lines.

Phosphoproteomic dynamics of chickpea (Cicer arietinum L.) reveals shared and distinct components of dehydration response.

Reversible protein phosphorylation is a ubiquitous regulatory mechanism that plays critical roles in transducing stress signals to bring about coordinated intracellular responses. To gain better understanding of dehydration response in plants, we have developed a differential phosphoproteome in a food legume, chickpea (Cicer arietinum L.). Three-week-old chickpea seedlings were subjected to progressive dehydration by withdrawing water, and the changes in the phosphorylation status of a large repertoire of proteins were monitored. The proteins were resolved by 2-DE and stained with phosphospecific fluorescent Pro-Q Diamond dye. Mass spectrometric analysis led to the identification of 91 putative phosphoproteins, presumably involved in a variety of functions including cell defense and rescue, photosynthesis and photorespiration, molecular chaperones, and ion transport, among others. Multiple sites of phosphorylation were predicted on several key elements, which include both the regulatory as well as the functional proteins. A critical survey of the phosphorylome revealed a DREPP (developmentally regulated plasma membrane protein) plasma membrane polypeptide family protein, henceforth designated CaDREPP1. The transcripts of CaDREPP1 were found to be differentially regulated under dehydration stress, further corroborating the proteomic results. This work provides new insights into the possible phosphorylation events triggered by the conditions of progressive water-deficit in plants.