A multi-dimensional approach from seed-to-seed to understand and improve heat stress tolerance in riceS KMangrauthiaauthorVVishnu PrasanthauthorBSailajaauthorNSarlaauthorS RVoletiauthorDSubrahmanyamauthorV RBabuauthorIn changing climatic conditions, stress caused by high temperature
poses a serious threat to rice cultivation. Physiological,
biochemical, and molecular analysis of rice cultivars revealed
that Nagina22 (N22) shows lesser reduction in chlorophyll content,
net photosynthetic rate, spikelet fertility and grain yield,
but increased membrane thermal stability, antioxidant enzymes
activity and transpiration rate (E) at high temperature. DREB,
RAB, LEA, and genes associated with hormones signalling were
induced during germination, while OsFd (an iron sulphur cluster
binding protein) and CWIP (cell wall integrity protein) emerged
as high priority candidate genes in seedling and reproductive
stages. Their function is being analysed by transgene expression
and CRISPR/Cas genome editing approaches. Field screening
in polyhouse, late sowing and temperature gradient chamber
for 20 morpho-physiological traits indicated the importance of
both yield and spikelet fertility, and photosynthesis traits. N22
showed the least Heat Susceptibility Index (HSI) for yield/plant,
spikelet fertility, flag leaf SPAD and stomatal conductance, while
Vandana showed the highest HSI for spikelet fertility and flag leaf
temperature. QTLs for HSI of spikelet fertility were identified on
chromosome 1 and HSI of yield per plant on chromosomes 1, 2, 3,
4, 7 and 8; and PV of 6% to 57% using 174 F2-3 Vandana x N22
mapping population. Simultaneously, RNAseq was performed
to identify the genome wide miRNAs and transcriptome of N22
and Vandana from shoot and root after short and long duration
of heat stress treatments; and recovery phase for an eQTL-guided
function-related co-expression analysis to identify the putative
regulators and gene regulatory networks.Abiotic StressCrop ImprovementRice2017-02Conference or Workshop Item