Genome-wide analysis of HSF genes and their role in the response to drought stress in wild and commercial Carica papaya L. genotypes

Autor: Beatriz Xoconostle

Revista: Scientia Horticulturae

Resumen: Heat shock transcription factors (HSFs) are a family of genes that are involved in plant development and in the response to biotic and abiotic stresses, including drought stress. HSFs are involved in regulating the expression of heat shock proteins (HSPs) by binding to heat stress elements (HSEs). The recent resequencing of the genome of Carica papaya cv. SunUp enables a more detailed in silico HSF genetic and functional study in this important species. In the present study, 19 CpHSF genes were identified. Phylogenetic analysis of HSF in Carica papaya and Arabidopsis thaliana revealed that they are closely related; both species showed a similar number (19 vs 21). As a result, they shared a similar phylogenetic tree with 3 well-defined classes (A, B, and C). Collinearity and synteny analysis indicated that the HSF family presented two events associated with genome expansion: a pair of tandem duplicated genes (CpHSFA9.1 and CpHSFA9.2) was identified, a single segmental duplication event between the CpHSFA6b and CpHSFA7a genes. The presence of cis-acting elements in the promoter regions of CpHSFs highlighted the regulatory role in response to light, high temperatures, ABA and drought inducibility. To determine the possible role of this family in the response mechanism to drought, experiments were carried out by exposing plants of 3 papaya genotypes to a period of 21 d water deficit stress (WDS). Our transcriptome results showed that the majority of CpHSF increased their expression when plants were exposed to 14d of WDS. Most importantly, it was clear that the wild genotype showed higher expression of various CpHSFs in response to drought, than the commercial genotype Maradol. Those results were confirmed using qRT-PCR of selected CpHSFs from plants exposed during 21 days to WDS. Again, the wild genotype had consistently higher expression of both CpHSFA1 and CpHSFB3, than the commercial genotype.

https://www.sciencedirect.com/science/article/pii/S0304423824000499