Expression profiling of HbWRKY1, an ethephon-induced WRKY gene in latex from Hevea brasiliensis in responding to wounding and drought

Abstract

A full-length WRKY cDNA, designated as HbWRKY1, was isolated from the latex in Hevea brasiliensis. The deduced HbWRKY1 contained 303 amino acid residues with one WRKY domain and one zinc-finger motif, and shared high identity to WRKYs from other plant species. The phylogenetic tree showed that HbWRKY1 was classified into group-II WRKYs. Many cis-acting elements related to hormone and stress responses were identified in the 1,377 bp-length 5 0 regulatory sequence of HbWRKY1, including three W-boxes, three ABREs, two MYBCOREs, one PRE, two OSE2ROOTNODULEs, one SEBFCONSSTPR10A and two HSEs. Semi-quantitative RT-PCR analysis revealed more significant accumulation of HbWRKY1 transcripts in latex and flowers than in bark, leaves and roots. The transcription of HbWRKY1 in latex was strongly induced by tapping and some wounding-signal molecules such as ethylene and jasmonic acid, and Oidium heveae attack, PEG and abscisic acid also strongly induced its expression in the leaves of H. brasiliensis. All these results suggest that HbWRKY1 mainly functions in responding to mechanical wounding, some wounding-related hormones, drought and O. heveae attack as an ethephoninduced WRKY transcriptional factor in H. brasiliensis.

Comprehensive Proteomics Analysis of Laticifer Latex Reveals New Insights into Ethylene Stimulation of Natural Rubber Production

“…Several reports have uncovered that the genes for certain regulated proteins, such as WRKY transcription factor 1 51 , 14-3-3 protein 52 , metallothionein 53 , and ethylene-responsive factor 41 44 and peroxidase 49 , responded positively to ethylene stimulation. Notably, some protein kinases, including CDPK 2 53 , MAPK 41 47 , serine/threonine protein kinase and CBL-interacting protein kinase 41 , were significantly induced in rubber latex by exogenous ethylene.…”

WRKY Transcription Factors: Molecular Regulation and Stress Responses in Plants

“…Ectopic expression of PqWRKY1 in Arabidopsis up-regulates genes involved in triterpene biosynthesis, indicating that WRKYs are capable of regulating metabolic pathways in other species. The expression of HbWRKY1 has been associated with increased biosynthesis of natural rubber, a polyisoprenoid derived from wounding the bark of the tropical tree Hevea brasiliensis ( Zhang et al, 2012 ). So directly or indirectly WRKYs regulate plant defense response and development by altering/enhancing secondary metabolite biosynthesis.…”

Molecular Cloning, Sequence Analysis and Expression Analysis of an NtWRKY6 from Tobacco (<i>Nicotiana tabacum</i> L.) in Abiotic Strsss

“…Arg.) in leaves was gradually up-regulated and came to its peak at 12 h after 20% PEG 6000 treatment [28]. So, we can conclude NtWRKY6 might be upstream regulator in salt and drought pathway.…”