Expression of the HEV2.1 gene promoter in transgenic Hevea brasiliensis

Abstract

Hevein is involved in the coagulation of rubber particles and is known to be highly expressed in latex cells from Hevea brasiliensis. As all HEVEIN genes are highly conserved in their transcribed region, a promoter functional analysis was carried out in transgenic rubber tree in order to evaluate the expression of HEV2.1, one member of the HEVEIN multigenic family. Three out of the 14 established independent transgenic lines carrying the HEV2.1:: GUS construct were selected and set to regenerate plantlets. In situ hybridization of transgenic and wildtype plant tissues was respectively carried out with gusA and HEVEIN antisense mRNA probes. This showed co-localized-expression of the HEV2.1 gene with the overall HEVEIN gene expression. Laticiferspecific expression was observed in roots and stems, but not in leaves where HEVEIN genes were expressed in all cell types. Since HEV2.1::GUS callus lines responded significantly to light stimulation, up-regulation of the expression of HEV2.1 genes by light was suggested in leaves.

Highlights on Hevea brasiliensis (pro)hevein proteins

“…Pascal Montoro et al used the HEV2.1 promoter to express GUS (β-glucuronidase) constructs in transgenic Hevea. Laticifer-specific expression was also observed in roots and stems, but not leaves [53]. In addition, HEV genes are expressed in all cell types of leaf tissues [53].…”

“…Laticifer-specific expression was also observed in roots and stems, but not leaves [53]. In addition, HEV genes are expressed in all cell types of leaf tissues [53]. In transgenic Hevea, light stimulated the expression of the pHEV2.1::GUS construct [53] whereas it was activated by a pathogenic fungus (M. grisea) or wounding in transgenic rice [39].…”

“…In addition, HEV genes are expressed in all cell types of leaf tissues [53]. In transgenic Hevea, light stimulated the expression of the pHEV2.1::GUS construct [53] whereas it was activated by a pathogenic fungus (M. grisea) or wounding in transgenic rice [39]. Various potential cis-regulatory elements in the 5' upstream region of pHEV1.1 and pHEV2.1 were also identified by in silico approaches [39].…”

Overexpression of Hevea brasiliensis ethylene response factor HbERF‐IXc5 enhances growth and tolerance to abiotic stress and affects laticifer differentiation

“…Although a Hevea gene was first inserted in transgenic rubber plants in 2003 (Jayashree et al ., ), the first complete functional analysis of a gene encoding a Hevea copper zinc superoxide dismutase was recently carried out in transgenic rubber (Leclercq et al ., ). Based on this effective procedure, the study sets out to produce and characterize transgenic rubber plants overexpressing the HbERF‐IXc5 gene under the transcriptional control of two promoters, CaMV 35S and Hev2.1 (Montoro et al ., ). Sixteen independent transgenic callus lines were established.…”

The effect of Agrobacterium densities and inoculation times on gene transformation efficiency in rubber tree

“…The target of transgene expression in latex cells was also attempted using the promoter from gene HEV2.1, which was the major latex Hevein protein (Montoro et al, 2008). Moreover, genetic transformation protocol was developed using the transfer of a synthetic CP4 EPSPS transgene, as a conditional positive selectable marker, into commercially relevant zonal pelargoniums using an A. tumefaciens strain in combination with a novel step-down glyphosate selection system.…”