مجله بیوتکنولوژی کشاورزی (Sep 2021)
Evaluation of HSP-70 heat-tolerance gene in Yaghooti grape of Sistan under hormonal treatment by Indole acetic acid, Gibberellic acid and Abscisic acid
Abstract
Objective Yaghooti seedless grape is one of the early-ripens variety of grapes in Iran where its fruit marketed by mid-May. This grape has high resistance to extreme heat of the region, which made Yaghooti grape one of the unique and exclusive products of the province and country. Heavy heat-shock proteins like HSP60, HSP70 and HSP90 seems to have key role in survival and rescue the plants against the heat-stress. By considering this unique feature of the plant and key role of the HSP-70 protein in said process studied and analyzed in all three stages of cluster growth and development under influence of hormonal treatment of abscisic acid, gibberellic acid and Indole-acetic acid. Materials and methods Plant materials used for total RNA extraction were sampled in three stages: cluster formation, berry formation and final size of cluster growth process. Specific primers of HSP-70 gene (1104687527) and Actin-7 gene (100232866) as housekeeping gene were designed by CLC main workbench and used for Real Time-PCR reaction. Finally, the relative expression was calculated based on the obtained Cts using Pfaffl formula. The results were analyzed using a completely randomized factorial design and Duncan test with a significance level of 0.01 using SAS 9.0 software. The co-expression network was rebuilt using Cytoscape software. Results The relatively highest expression obtained for the HSP-70 at the 2nd stage of development simultaneously with the flowering and under influence of abscisic hormonal treatment. Elevation in the level of abscisic acid resulted in upregulation of ABI2 gene that subsequently supresses the internal synthesis of abscisic acid hormone and upregulation of HSP-70. Conclusions Abscisic acid in compare with Indole-acetic acid and gibberellin hormone has key role in upregulation and heat-resistance induction in Yaghooti grape. Hormone-treated clusters in comparison to the control clusters had lesser congestion and density. Gibberellin treatment cause the increase in length of cluster in addition to decrease in grapes number per cluster.
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