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The AP2/ERF superfamily is one of the largest groups of transcription factors (TFs) in plants, which plays important roles in regulating plant growth and development under heat stress. A complete genome-wide identification, characterization, and expression analysis of AP2/ERF superfamily genes focusing on heat stress response were conducted in bread wheat. This study identified 630 putative AP2/ERF superfamily TF genes in wheat, with 517 genes containing well-defined AP2-protein domains. They were classified into five sub-families, according to domain content, conserved motif, and gene structure. The unique genes identified in this study were 112 TaERF genes, 77 TaDREB genes, four TaAP2 genes, and one TaRAV gene. The chromosomal distribution analysis showed the unequal distribution of TaAP2/ERF genes in 21 wheat chromosomes, with 127 pairs of segmental duplications and one pair of tandem duplication, highly concentrated in TaERF and TaDREB sub-families. The qRT-PCR validation of differentially expressed genes (DEGs) in contrasting wheat genotypes under heat stress conditions revealed that significant DEGs in tolerant and susceptible genotypes could unequivocally differentiate tolerant and susceptible wheat genotypes. This study provides useful information on TaAP2/ERF superfamily genes and reveals candidate genes in response to heat stress, which forms a foundation for heat tolerance breeding in wheat.

As important regulators of alternative splicing (AS) events, serine/arginine (SR)-rich proteins play indispensable roles in the growth and development of organisms. Until now, the study of SR genes has been lacking in plants. In the current study, we performed genome-wide analysis on the SR gene family in rice. A total of 24 OsSR genes were phylogenetically classified into seven groups, corresponding to seven subfamilies. The OsSR genes' structures, distribution of conserved domains, and protein tertiary structure of OsSR were conserved within each subfamily. The synteny analysis revealed that segmental duplication events were critical for the expansion of OsSR gene family. Moreover, interspecific synteny revealed the distribution of orthologous SR gene pairs between rice and Arabidopsis, sorghum, wheat, and maize. Among all OsSR genes, 14 genes exhibited NAGNAG acceptors, and only four OsSR genes had AS events on the NAGNAG acceptors. Furthermore, the distinct tissue-specific expression patterns of OsSR genes showed that these genes may function in different developmental stages in rice. The AS patterns on the same OsSR gene were variable among the root, stem, leaf, and grains at different filling stages, and some isoforms could only be detected in one or a few of tested tissues. Meanwhile, our results showed that the expression of some OsSR genes changed dramatically under ABA, GA, salt, drought, cold or heat treatment, which were related to the wide distribution of corresponding cis-elements in their promoter regions, suggesting their specific roles in stress and hormone response. This research facilitates our understanding of SR gene family in rice and provides clues for further exploration of the function of OsSR genes. [ABSTRACT FROM AUTHOR]

• HuHMA gene family exhibited unique expression patterns in the growth and development of pitaya. • Transcriptome analysis revealed that HMA-1/11//18/19/28/29 genes exhibited significantly higher expression in single and combined multifactorial stresses. • Comprehensive genome-wide characterization and expression profiling revealed the diverse role of HMA gene members under abiotic stresses and melatonin-mediated tolerance in pitaya. • Exogenous application of melatonin mitigates the effect of combined stresses and HMA gene family members exhibited significantly higher expression. Plants have evolved various ways to improve their tolerance against heavy metal stress including physiological, biochemical, and molecular pathways. The heavy metal-associated (HMA) gene family plays an important role in the detoxification of metal ions. Research on HMA protein diversification, expression, and function in S. undatus is limited. In this study, we have identified 29 HMA proteins andrenamed them as HuHMA-1 to HuHMA-29. Our genome-wide characterization analysis supports the classification of HuHMA gene family members into 11 subfamilies based on their phylogenetic tree topology and conserved motif domains. RNA-Seq analysis exhibited varied expression in pitaya tissues at different developmental stages where we found HuHMA-1 & 16 gene family members strongly expressed in flower buds, flower, pericarp and pulp. Duplication event and Ka/Ks ratio depict that most of the HuHMA genes are generated by segmental duplication, except two pairs of the genes (HuHMA18-HuHMA20 and HuHMA28-HuHMA29) originated through proximal duplication mapped on Chr07 and Chr11. Transcriptome analysis of single and multifactorial stress-treated plants revealed candidate genes (HMA-1/11/18/19/28/29) that might play diverse functions to ameliorate the impact of heavy metal stresses individually and the combined effect of heat and drought. These HMA gene family members exhibited significantly higher expression under multifactorial stresses. The present analysis provides a theoretical foundation for the functional study through advanced biotechnological tools and provides novel insight into the structure and evolution of the HuHMA genes. [ABSTRACT FROM AUTHOR]