Biochemical Defense Response: Characterizing the Plasticity of Source and Sink in Spring Wheat under Terminal Heat Stress

Abstract

Wheat is highly prone to terminal heat stress (HS) under late-sown conditions. Delayed- sowing is one of the preferred methods to screen the genotypes for thermotolerance under open field conditions. We investigated the effect of terminal HS on the thermotolerance of four popular genotypes of wheat i.e. WR544, HD2967, HD2932, and HD2285 under field condition. We observed significant variations in the biochemical parameters like protein content, antioxidant activity, proline and total reducing sugar content in leaf, stem, and spike under normal (26 ± 2°C) and terminal HS (36 ± 2°C) conditions. Maximum protein, sugars and proline was observed in HD2967, as compared to other cultivars under terminal HS. Wheat cv. HD2967 showed more adaptability to the terminal HS. Differential protein-profiling in leaves, stem and spike of HD2967 under normal (26 ± 2°C) and terminal HS (36 ± 2°C) showed expression of some unique protein spots. MALDI-TOF/MS analysis showed the DEPs as RuBisCO (Rub), RuBisCO activase (Rca), oxygen evolving enhancer protein (OEEP), hypothetical proteins, etc. Expression analysis of genes associated with photosynthesis (Rub and Rca) and starch biosynthesis pathway (AGPase, SSS and SBE) showed significant variations in the expression under terminal HS. HD2967 showed better performance, as compared to other cultivars under terminal HS. SSS activity observed in HD2967 showed more stability under terminal HS, as compared with other cultivars. Triggering of different biochemical parameters in response to terminal HS was observed to modulate the plasticity of carbon assimilatory pathway. The identified DEPs will enrich the proteomic resources of wheat and will provide a potential biochemical marker for screening wheat germplasm for thermotolerance. The model hypothesized will help the researchers to work in a more focused way to develop terminal heat tolerant wheat without compromising with the quality and quantity of grains.

Continuous Light Does Not Compromise Growth and Yield in Mini-Cucumber Greenhouse Production with Supplemental LED Light

“…However, in our study, no CL-injury was observed from T2. Similar J max :V cmax values between light treatments ( Table 3 ) indicate that photosynthesis under CL is not preferentially inhibited by either electron transport or RuBP regeneration, as was the case in Haque et al [ 31 ]. Notably, V cmax and J max from T2 were decreased at both 19 and 96 DIT measurements compared to the other treatments ( Table 3 ).…”

“…The high-pressure mercury lamp emits much more thermal radiation than LEDs which may lead to high top canopy temperature and stress. It has been shown that tomatoes grown under CL with a constant temperature had developed CL related injury [ 31 ]. However, when exposed to a decrease in nighttime temperature, tomato plants grown under CL were not observed to have typical traits associated with CL-injury [ 31 ].…”

“…It has been shown that tomatoes grown under CL with a constant temperature had developed CL related injury [ 31 ]. However, when exposed to a decrease in nighttime temperature, tomato plants grown under CL were not observed to have typical traits associated with CL-injury [ 31 ]. Thus, due to the reduction in radiant heat emitted from LED fixtures (55% of output energy for HPS compared to 27% for LED), LEDs can reduce the heat load enough during the night to mitigate CL-injury, allowing for the use of such production strategies.…”

Stay-Green Trait: A Prospective Approach for Yield Potential, and Drought and Heat Stress Adaptation in Globally Important Cereals

“…An increase in leaf area, rate and duration of grain filling and photosynthetic competence, water use efficiency, leaf anatomy, have been found to be a characteristic for the SG trait [24,29] (Figure 3). It has been reported that breeding with a SG phenotype can improve yield under post-flowering drought stress (terminal drought stress), without yield penalties in environments not affected by drought [24,30,31].…”

Insight into the mechanisms of terminal HS-tolerance in wheat mutant with improved nutritional quality through de novo transcriptome sequencing

“…Potential SNPs were observed lying on HSP, SOD, STK, MYB, bZIP, Universal stress protein, and PPIase, which might have changed the thermal stability of these proteins under HS in mutant. These genes have been reported earlier to be potential SAGs involved in modulating thermotolerance in wheat 56 . We also observed potential InDels lying on starch synthase (prominent enzyme of starch biosynthesis pathway), and STKs (MAPK cascade) providing the structural stability and high activities in wheat mutant under heat stress.…”