Title : Finding of novel EST Marker associated with grain filling duration and tillering traits in Wheat (Triticum aestivum L.) under terminal heat stress
Abstract:
Terminal heat stress is a significant abiotic factor affecting wheat production, causing substantial yield loss despite the plant’s ability to develop heat tolerance mechanisms. Expressed Sequence Tags (ESTs) are valuable tools for studying these mechanisms, as they represent genes involved in the plant’s response to heat stress. By utilizing ESTs, we can identify genes that are crucial for triggering the plant's reaction to terminal heat stress. In this study, we conducted In-silico design of EST markers using existing wheat endosperm tissue sequences from NCBI. Bioinformatics tools were employed to design markers with specific parameters, such as higher GC content. The study was carried out in the Krishi Vigyan Kendra, Banasthali Vidyapith, Tonk, Rajasthan; India over three crop seasons (2022-2024), with wheat genotypes sown under two conditions: timely sowing (mid-November) and late sowing (mid-December). This setup exposed the plants to varying temperature, simulating terminal heat stress. We recorded grain filling duration and reduction percentage of tillers (timely and late sown) to assess the impact of heat stress on wheat. To further analyze the relationship between the in-silico designed EST markers and the observed traits, we calculated the Heat Susceptibility Index (HSI) for each genotype. The HSI helped us classify genotypes based on their heat tolerance, with genotypes like DBW90 (0.69), DBW107 (0.93), and DBW222 (0.3) showing heat tolerance, while HD2177 (1.04), GW190 (1.26), and HD2501 (1.06) were identified as heatsensitive based on their tillering response. The co-relation of phenotypic variations with EST markers provided valuable insights into the genetic basis of heat tolerance in wheat. By analyzing the percentage of phenotypic variation
linked to these markers, we identified putative markers for terminal heat tolerance in wheat. These markers can be utilized in plant breeding programs to develop wheat varieties with enhanced heat resilience in future agricultural systems. In summary, this study integrates bioinformatics approaches and field-based observations to design EST markers linked to heat stress tolerance, providing a foundation for advancing marker-assisted breeding aimed at improving wheat performance under terminal heat stress conditions.
Keywords: Wheat, EST markers, Marker-assisted breeding, Terminal heat tolerance, In-Silico
