Biology subjects

Shekhawat, K.

Publications and source records attributed to Shekhawat, K..

4 recordsLinked to original sources

bioRxiv2025

m6A RNA methylation attenuates thermotolerance in Arabidopsis

Heat stress severely affects plant growth, causing significant crop yield losses. To counteract this, plants employ adaptive strategies, including chromatin and transcriptional regulation of heat stress-related genes. However, the role of RNA methylation in heat stress response remains unclear. This study identifies m6A RNA methylation as a negative regulator of thermotolerance in Arabidopsis. Loss of m6A modification enhances resilience to heat stress by increasing transcript levels of heat-responsive genes and stabilizing their mRNAs. Upon heat shock, plants transiently reduce m6A levels by modulating key methylation machinery genes. This m6A deficiency enriches the H3K4me3 histone mark at heat-responsive gene loci, boosting their transcription. The combined effect of m6A-regulated chromatin changes and mRNA stability facilitates the accumulation of heat shock proteins essential for cellular protection and stress response. These findings reveal an interplay between m6A RNA methylation and histone modifications, forming a regulatory network that fine-tunes gene expression during heat stress. This novel mechanism highlights m6A as a critical regulator of plant thermotolerance, offering a promising target for improving heat stress resilience in crops.

plant biology↗

bioRxiv2025

USP1 acts as a chaperone for HSFA2 and plays a crucial role in thermopriming in Arabidopsis

Plants employ diverse strategies to cope with different types of heat stress. The response to short-term acute heat stress differs significantly from that to moderate heat stress followed by severe stress events. After experiencing moderate heat stress, plants exhibit a more robust response to subsequent severe stress, a phenomenon known as thermopriming or acquired thermotolerance. Thermopriming creates a memory by maintaining the heat stress (HS) memory-related genes in an alert state. In this work, we investigated the role of Arabidopsis Universal Stress Protein 1 (USP1) in plant heat stress responses. CRISPR-Cas9 generated knockout usp1 mutant lines showed no morphological changes during development and normal growth conditions. However, usp1 mutant plants showed enhanced levels of apoplast hydrogen peroxide and superoxide reactive oxygen species accumulation upon heat stress. Transcriptome analyses revealed that genes related to protein folding, electron transport, and oxidative phosphorylation are strongly upregulated in usp1 mutant plants. USP1 is essential for acquired thermotolerance, as usp1 mutants are compromised in heat stress memory but show normal responses to acute heat stress similar to hsfa2 mutants. Biochemical assays showed that USP1 functions as a molecular chaperone, protecting the transcription factor HSFA2 from heat-induced denaturation. Moreover, usp1 mutant plants show decreased transcript levels of heat stress response genes and reduced H3K4me3 enrichment at memory gene loci. These data show that USP1 plays an important role as a chaperone of HSFA2 in mediating plant heat stress memory.

biochemistry↗

bioRxiv2020

Diversified agroforestry systems improve carbon footprint and farmers livelihood under limited irrigation conditions

Increasing weather aberrations cause frequent crop failure in monoculture cropping system. Specialized crop production systems, where few seasonal crops occupy vast arable lands, resulting in more biotic and abiotic stresses in agri-ecosystem. Therefore a diversified agroforestry systemwas evaluated to ensure resilience underlimited water conditions, with an aim to augment carbon footprint with enhanced productivity and profitability. The study hypothesised that integration of perennial fruits trees with seasonal crops will have benign effect for sequestering more carbon and improving livelihood of the farmers. This is one of the first timesthat arid fruits tress along with leguminous,and other low water requiring crops were studied for improved carbon sequestration, livelihood of the farmers andfor better resilience in production system. The experimental findings showed that arid fruit trees along with leguminous, oilseeds and cash crops resulted in higher profitability and thus improved livelihood of the farmersin arid and semi-arid areas of South Asia. Diversified phalsa-mung bean-potato and moringa-mung bean-potato were the most productive agroforestry system (36.7t/ha and 36.2 t/ha respectively. Under limited irrigation conditions, Karonda (Carisa spp.)-mung bean potato system was found best in improving livelihood with maximum net return of $ 3529.1/ha with higher profitability/day ($ 19.9/day). Phalsa -MB-potato system was also recorded maximum water use efficiency (33.0 kg/ha-mm), whereas density of SOC was in Phalsa-cowpea-mustard (9.10 Mg/ha) and moringa-mung bean -potato AFS (9.16 Mg/ha). Carbon footprint analysis revealed that maximum net C gain was in Phalsa-mung bean -potato system (7030 Carbon equivalent kg CE/ha/year).

ecology↗

bioRxiv2020

Enterobacter sp. SA187 mediates plant thermotolerance by chromatin modification of heat stress genes

Global warming has become a critical challenge to food safety, causing severe yield losses of major crops worldwide. Heat acclimation empowers plants to survive under extreme temperature conditions but the potential of beneficial microbes to make plants thermotolerant has not been considered so far. Here, we report that the endophytic bacterium Enterobacter sp. SA187 induces heat tolerance in Arabidopsis thaliana by reprogramming the plant transcriptome to a similar extent as acclimation. Acclimation induces priming of heat stress memory genes such as APX2 and HSP18.2 via the transcription factors HSFA1A, B, D, and E and the downstream master regulator HSFA2. hsfa1a,b,d,e and hsfa2 mutants compromised both acclimation and bacterial priming through the same pathway of HSF transcription factors. However, while acclimation transiently modifies H3K4me3 levels at heat stress memory gene loci, SA187 induces the constitutive priming of these loci. In summary, we demonstrate the molecular mechanism by which SA187 imparts thermotolerance in A. thaliana, suggesting that beneficial microbes might be a promising way to enhance crop production under global warming conditions.

plant biology↗