Plant Hormone Stimulation and HbHSP90.3 Plays a Vital Role in Water Deficit of Rubber Tree (Hevea brasiliensis Muell. Arg.)

The yield and quality of rubber tree latex are affected by environmental stresses and plant hormone stimulation. Heat shock protein 90 (HSP90) is widely involved in various developmental processes and stress responses in plants, especially in drought stress. In this study, we cloned the <i>HbHSP90.3</i> gene and characterized its expression pattern in different tissues and mechanical wounding treatments of the rubber tree and found that it is highly expressed in latex and responds to mechanical wounding treatment. To reveal the roles of plant hormones and HSP90.3 protein in the drought resistance process of rubber trees. Treatment with the specific HSP90 protein inhibitor geldanamycin (GDA) and yeast expression experiments demonstrated that <i>HbHSP90.3</i> has a relieving effect on water deficit in rubber trees. The expression pattern showed that the <i>HbHSP90.3</i> gene was closely related to hormone signaling, especially for Indole acid (IAA) and Zeatin (ZT) induction under different plant hormone treatments. Protein interaction analysis showed that HbHSP90.3 interacted with the suppressor of the G2 allele of skp1 (HbSGT1b). Taken together, HbHSP90.3 interacts with HbSGT1b in the nucleus and plays a key role in water deficit.