Sequence and Expression Analyses of Ethylene Response Factors Highly Expressed in Latex Cells from Hevea brasiliensis

Abstract

The AP2/ERF superfamily encodes transcription factors that play a key role in plant development and responses to abiotic and biotic stress. In Hevea brasiliensis, ERF genes have been identified by RNA sequencing. This study set out to validate the number of HbERF genes, and identify ERF genes involved in the regulation of latex cell metabolism. A comprehensive Hevea transcriptome was improved using additional RNA reads from reproductive tissues. Newly assembled contigs were annotated in the Gene Ontology database and were assigned to 3 main categories. The AP2/ERF superfamily is the third most represented compared with other transcription factor families. A comparison with genomic scaffolds led to an estimation of 114 AP2/ERF genes and 1 soloist in Hevea brasiliensis. Based on a phylogenetic analysis, functions were predicted for 26 HbERF genes. A relative transcript abundance analysis was performed by real-time RT-PCR in various tissues. Transcripts of ERFs from group I and VIII were very abundant in all tissues while those of group VII were highly accumulated in latex cells. Seven of the thirty-five ERF expression marker genes were highly expressed in latex. Subcellular localization and transactivation analyses suggested that HbERF-VII candidate genes encoded functional transcription factors.

The rubber tree genome reveals new insights into rubber production and species adaptation

“…A total of 225 Hevea AP2/ERF members, including 181 ERFs, 35 AP2s, 7 RAVs and 2 Soloists (Supplementary Table 26) were identified, representing the largest assemblage in this grouping as compared to other plants (Supplementary Table 27) 37 . Nearly one-tenth of the AP2/ERF members showed a more than twofold change in expression after ethylene treatment; 10 of them were upregulated and 11 downregulated (Supplementary Table 28).…”

The Hevea brasiliensis AP2/ERF superfamily: from ethylene signalling to latex harvesting and physiological disease response

“…The transcript accumulation of AP2/ERF genes was analyzed during the process of somatic embryogenesis from callus lines with different regeneration capacity in various vegetative and reproductive tissues (Piyatrakul et al, 2012). Secondly, Piyatrakul et al (2014) focused the experiment on the search for ERF family having an important role in the laticifers related to the latex production. The transcriptomic database was improved by supplementing RNA samples from reproductive tissues (immature and mature male flowers, immature and mature female flowers, and zygotic embryos).…”

“…The ERF-VII was characterized by a protein motif MCGGAI(I/L) at the N-terminus (van Veen et al, 2014;Piyatrakul et al, 2014;Nakano et al, 2006). This N-end rule regulation was associated with the targeted protein degradation by the proteasome (Licausi et al, 2011).…”

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

“…Two orthologues to Arabidopsis ERF1 have been predicted in the rubber tree (Putranto et al ., ). These genes, HbERF‐IXc4 and HbERF‐IXc5 , are highly expressed in bark and latex tissues (Piyatrakul et al ., ). They are also activated in the latex from tapped or ethephon‐stimulated trees, and in leaves of plants grown under abiotic stress (Putranto et al ., ).…”