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BOOK OF ABSTRACTS 20 19 Wheat Productivity Enhancement through Climate Smart Practices February 14-16 2019 | CSK HPKV Palampur HP India 4 INTERNA TIONAL TH GROUP MEETING TH 4 IGM-2019

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High temperatures during grain illing stage directly affect the metabolism growth duration and grain illing rates as well as quality grain maturity and hence overall yield of wheat. During heat stress miRNAs act as signiicant regulatory factors in controlling gene expression by repressing translation or promoting degradation of the target mRNA. In this study 36 wheat genotypes were evaluated for heat tolerance under controlled and stress conditions for two consecutive years at ICAR-IIWBR. On the basis of precision phenotyping Raj 3765 heat tolerant and HUW 510 heat susceptible were chosen for miRNA studies. Four small RNA libraries were prepared from developing seeds at 10 days after anthesis from the two genotypes grown in normal and heat stress conditions. High-throughput sequencing and its analysis revealed 76 conserved miRNAs mostly belonging to MIR156 MIR159b MIR160 MIR398 families and 80 novel miRNAs. To gain an insight of the functions of the novel miRNAs identiied the putative targets of these miRNAs were predicted. Gene Ontology and KEGG pathway enrichment analyses of the expressed miRNAs indicated their involvement in signal transduction e.g. MAPK cascade carbohydrate transport and metabolism chaperone binding reactive oxygen species ROS metabolic process e.g. hydrogen peroxide catabolism hormone-mediated signaling pathways e.g. auxin abscisic acid- activated signaling pathways and transcription factors e.g. MYB ZFP MYC bZIP. Through degradome sequencing the targets of miRNAs degradation sites and cleavage products were identiied. The cleaved targets of various miRNAs were found to correspond to transcripts involved in seed development cell division cell size seed maturation and heat stress responses. These observations indicate the miRNA driven regulation of gene expression and how these miRNAs inluence the regulatory pathways involved in wheat’s heat stress response during seed developing stage. O3.2 Exploring heat stress responsive microRNAs and their targets in developing seeds of wheat using small RNA and degradome proiling 1 1 2 1 1 Monika Saroha Geetika Mehta Aditi Arya GP Singh and Pradeep Sharma 1 ICAR- Institute of Wheat and Barley Research Karnal 132001 Haryana 2 Deenbandhu Chhotu Ram University of Science and Technology Murthal Haryana Pradeep.Sharmaicar.org.in 80 th 4 IGM at CSKHPKV Palampur from 14-16 February 2019 Abiotic stress in relation to climate change