Abstract:
The secondary laticifer is the position for synthesis and storage of natural rubber (NR),
which is differentiated from the vascular cambium of bark in stem of rubber trees (Hevea
brasiliensis). The quantity of secondary laticifer is depend on the frequency of the secondary
laticifer differentiation from cambia, which is the main index of yield breeding of rubber tree. In
previous studies, we found trichostatin A (TSA), an inhibitor of histone deacetylase (HDA), can
also induce laticifer differentiation, and the histone deacetylase gene (HbHDA6) is a participator
in laticifer differentiation. Because of the molecular mechanism of secondary laticifer
differentiation regulated by histone acetylation has not been clarified. So, we construct a yeast
two-hybrid cDNA library used the vascular cambium tissues treatment by coronatine (COR), and
screening the yeast two-hybrid library by HbHDA6 gene as the bait, for determining the proteins
interacting with HbHDA6. The results were as follows: (1) The homogenized yeast two-hybrid
cDNA library of vascular cambium is successful and constructed by the technology of gateway.
The capacity of the primary library is 6.3 × 106, the total number of clones is 1.2 × 107, and the
capacity of secondary library is 7.7 × 106, the total number of clones is 1.5 × 107, the
recombination rate of the libraries is 100%. (2) The average length of inserted fragments is 1.1 kb
and 1.2 kb in primary and secondary library, respectively. The bait vector of pGBKT7-HbHDA6 is
constructed and confirmed no self-activation activity. (3) The cDNA library is screened with the
pGBKT7-HbHDA6 bait vector, found 22 proteins interacting with HbHDA6, including CLP1,
ERF3, ERF4, HSP82, LARP6a, APT5, PP2A, APT5, FBA6, etc. The results provide a theoretical
basis for analyzing the molecular regulatory network of the secondary laticifer differentiation of
rubber tree, and provide candidate genes for the rubber production potential of genetically
modified and a new clue for the genetic improvement and breeding of high-performance NR.