Genome-wide Identification And Functional Analysis Of The BES1/BZR1 In Hevea Brasiliensis

Hevea brasiliensis is the main source of commercial natural rubber,while the mechanism of latex metabolism is still unclear.Transcription factors play important roles in regulating gene expression and signal transduction.The BES1/BZR1 transcription factor mediates BR signaling and involved in signaling pathways such as ABA,GA,light signaling and ethylene.Therefore,a preliminary understanding of the molecular regulation mechanism of BES1/BZR1 transcription factors and the discovery of their regulatory network will provide a basis for further analysis of the rubber tree latex production and exclusion mechanism.In this study,12 members of the HbBES1/BZR1 gene family were identified for the first time at the genome-wide level.A total of eight genes expressed in latex,HbBES1-1,HbBES1-2,HbBES1-4,HbBES1-6,HbBES1-7,HbBES1-8,HbBES1-9and HbBES1-12,were successfully cloned for in-depth study,laying the foundation for resolving the regulatory role of HbBES1/BZR1 in laticiferous metabolism.The main results are as follows.1.Twelve members of the HbBES1/BZR1 gene family,named HbBES1-1,HbBES1-2,HbBES1-3,HbBES1-4,HbBES1-5,HbBES1-6,HbBES1-7,HbBES1-8,HbBES1-9,HbBES1-10,HbBES1-11 and HbBES1-12,were identified in the rubber tree genome.2.Expression analysis using RNA-seq data showed that HbBES1-4 and HbBES1-8 were members of the HbBES1/BZR1 gene family that responded significantly to ethylene treatment and tapping stimuli in latex.3.A total of 205 genes were predicted as potential targets genes of HbBES1/BZR1 gene family members in the whole rubber tree genome using FIMO software.Further,79 candidate target genes were screened in combination with the expression of the target genes in latex.5.The promoter sequences of Hb TAF12 B,Hb TIF3C1 and Hb Dna J were clarified to be physically interacting with HbBES1-4 by Yeast One-hybrid System.6.Eight genes,HbBES1-1,HbBES1-2,HbBES1-4,HbBES1-6,HbBES1-7,HbBES1-8,HbBES1-9 and HbBES1-12 were successfully translated into Arabidopsis thaliana by using agrobacterium-mediated transgenic technology.The seeds of T1 generation transgenic Arabidopsis were obtained.