The () gene family in : genome-wide identification and their expression profiling under heat and drought stresses.

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Auxin response factors (ARFs), as the main components of auxin signaling, play a crucial role in various processes of plant growth and development, as well as in stress response. So far, there have been no reports on the genome-wide identification of the ARF transcription factor family in , a deciduous tree plant in the family Juglaceae. In this study, a total of 34 genes were identified based on whole genome sequence, and they were unevenly distributed on 16 chromosomes, with the highest distribution on chromosome 6. Domain analysis of CpARF proteins displayed that 31 out of 34 CpARF proteins contain a typical B3 domain (DBD domain), except CpARF12/ CpARF14/CpARF31, which all belong to Class VI. And 20 CpARFs (58.8%) contain an auxin_IAA binding domain, and are mainly distributed in classes I, and VI. Phylogenetic analysis showed that CpARF was divided into six classes (I-VI), each containing 4, 4, 1, 8, 4, and 13 members, respectively. Gene duplication analysis showed that there are 14 segmental duplications and zero tandem repeats were identified in the gene family of the genome. The Ka/Ks ratio of duplicate gene pairs indicates that genes are subjected to strong purification selection pressure. Synteny analysis showed that shared the highest homology in 74 gene pairs with a, followed by 73, 51, 25, and 11 homologous gene pairs with , , , and rice, respectively. Promoter analysis revealed that 34 genes had elements related to hormones, stress, light, and growth and development except for . The expression profile analysis showed that almost all genes were differentially expressed in at least one tissue, and several genes displayed tissue-specific expression. Furthermore, 24 out of the 34 genes have significantly response to drought stress ( < 0.05), and most of them (16) being significantly down-regulated under moderate drought treatment. Meanwhile, the majority of genes (28) have significantly response to drought stress ( < 0.05), and most of them (26) are significantly down-regulated under severe drought treatment. Furthermore, 32 out of the 34 genes have significantly response to high, middle, and low salt stress under salt treatment ( < 0.05). Additionally, subcellular localization analysis confirmed that CpARF16 and CpARF32 were all localized to nucleus. Thus, our findings expand the understanding of the function of genes and provide a basis for further functional studies on genes in .

SUPPLEMENTARY INFORMATION

The online version contains supplementary material available at 10.1007/s12298-024-01474-1.