Genome-Wide Transcriptome Analysis During Anthesis Reveals New Insights into the Molecular Basis of Heat Stress Responses in Tolerant and Sensitive Rice Varieties

Abstract

Rice is one of the main food crops in the world. In the near future, yield is expected to be under pressure due to unfavorable climatic conditions, such as increasing temperatures. Therefore, improving rice germplasm in order to guarantee rice production under harsh environmental conditions is of top priority. Although many physiological studies have contributed to understanding heat responses during anthesis, the most heat-sensitive stage, molecular data are still largely lacking. In this study, an RNA-sequencing approach of heat- and control-treated reproductive tissues during anthesis was carried out using N22, one of the most heat-tolerant rice cultivars known to date. This analysis revealed that expression of genes encoding a number of transcription factor families, together with signal transduction and metabolic pathway genes, is repressed. On the other hand, expression of genes encoding heat shock factors and heat shock proteins was highly activated. Many of these genes are predominantly expressed at late stages of anther development. Further physiological experiments using heat-tolerant N22 and two sensitive cultivars suggest that reduced yield in heat-sensitive plants may be associated with poor pollen development or production in anthers prior to anthesis. In parallel, induction levels of a set of heat-responsive genes in these tissues correlated well with heat tolerance. Altogether, these findings suggest that proper expression of protective chaperones in anthers is needed before anthesis to overcome stress damage and to ensure fertilization. Genes putatively controlling this process were identified and are valuable candidates to consider for molecular breeding of highly productive heat-tolerant cultivars.

Integrating Omics and Alternative Splicing Reveals Insights into Grape Response to High Temperature

“…With cDNA microarrays and semiquantitative RT-PCR techniques, Frank et al (2009) found that HSP70, HSP90, and the heat shock transcription factors (HSF) HSFA2 and HSFA3 were important to tomato (Solanum lycopersicum) microspore resistance to heat stress. González-Schain et al (2016) conducted genome-wide transcriptomic analyses during anthesis and revealed new insights into the molecular basis of heat stress responses in tolerant and sensitive rice (Oryza sativa) varieties. In addition, proteomic responses to heat stress have been studied in some species, and various organs have been analyzed (Kosová et al, 2011).…”

Unraveling Field Crops Sensitivity to Heat Stress: Mechanisms, Approaches, and Future Prospects

“…Many modern approaches such as RNA-sequencing have led to various deep expression investigations, ultimately unraveling various heat-responsive candidate genes in several crops [36,232,233]. Transcriptomic investigations of HS effects on rice, wheat, tomato, grape, and tobacco have been reported [36,134,234].…”

<strong>When water runs dry and temperature heats up: </strong><strong>Understanding the mechanisms in rice tolerance to drought and </strong><strong>high temperature stress conditions</strong>

“…Several studies on comprehensive transcriptomics and metabolic analyses on the effect of drought and heat stresses on rice had been reported (González-Schain et al, 2016, Glaubitz et al, 2016, Li et al, 2015a. Figure 7 summarizes the chromosomal location of various genes in rice that have been identified for drought and heat tolerance.…”