title: 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.
authors.affiliation: Dipartimento di Bioscienze, Università degli Studi di Milano, via Celoria 26, 20133 Milan, Italy Present address: Instituto de Biología Molecular y Celular de Rosario (IBR), Universidad Nacional de Rosario, CONICET, Ocampo y Esmeralda, Rosario 2000, Argentina.
authors.forename: Nahuel
authors.initials: N
authors.lastname: González-Schain
authors.affiliation: Dipartimento di Bioscienze, Università degli Studi di Milano, via Celoria 26, 20133 Milan, Italy Present address: School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China.
authors.forename: Ludovico
authors.initials: L
authors.lastname: Dreni
authors.affiliation: Crop and Environmental Sciences Division, International Rice Research Institute, DAPO Box 7777, Metro Manila, Philippines Present address: Max Planck Institute of Molecular Plant Physiology, D-14476 Potsdam, Germany.
authors.forename: Lovely M F
authors.initials: LM
authors.lastname: Lawas
authors.affiliation: Dipartimento di Bioscienze, Università degli Studi di Milano, via Celoria 26, 20133 Milan, Italy.
authors.forename: Massimo
authors.initials: M
authors.lastname: Galbiati
authors.affiliation: Dipartimento di Bioscienze, Università degli Studi di Milano, via Celoria 26, 20133 Milan, Italy.
authors.forename: Lucia
authors.initials: L
authors.lastname: Colombo
authors.affiliation: Australian Centre for Plant Functional Genomics (ACPFG), Adelaide, Australia.
authors.forename: Sigrid
authors.initials: S
authors.lastname: Heuer
authors.affiliation: Crop and Environmental Sciences Division, International Rice Research Institute, DAPO Box 7777, Metro Manila, Philippines Present address: Department of Agronomy, 2004 Throckmorton Plant Science Center, Kansas State University, Manhattan, KS 66506, USA.
authors.forename: Krishna S V
authors.initials: KS
authors.lastname: Jagadish
authors.affiliation: Dipartimento di Bioscienze, Università degli Studi di Milano, via Celoria 26, 20133 Milan, Italy martin.kater@unimi.it.
authors.forename: Martin M
authors.initials: MM
authors.lastname: Kater
mesh_terms: D035264:Flowers / Q000235:genetics / Q000254:growth & development / Q000502:physiology; D020869:Gene Expression Profiling; D018506:Gene Expression Regulation, Plant; D063990:Gene Ontology; D006360:Heat-Shock Proteins / Q000235:genetics; D018869:Heat-Shock Response / Q000235:genetics*; D006358:Hot Temperature; D012275:Oryza / Q000235:genetics* / Q000254:growth & development / Q000502:physiology; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D017423:Sequence Analysis, RNA
chemical_list: D006360:Heat-Shock Proteins; D010940:Plant Proteins
keywords: Anthesis; Heat stress; Pollen; RNA-seq; Rice; Spikelet fertility