Transcriptome Analysis of the Signalling Networks in Coronatine-Induced Secondary Laticifer Differentiation from Vascular Cambia in Rubber Trees

Abstract

The secondary laticifer in rubber tree (Hevea brasiliensis Muell. Arg.) is a specific tissue within the secondary phloem. This tissue differentiates from the vascular cambia, and its function is natural rubber biosynthesis and storage. Given that jasmonates play a pivotal role in secondary laticifer differentiation, we established an experimental system with jasmonate (JA) mimic coronatine (COR) for studying the secondary laticifer differentiation: in this system, differentiation occurs within five days of the treatment of epicormic shoots with COR. In the present study, the experimental system was used to perform transcriptome sequencing and gene expression analysis. A total of 67,873 unigenes were assembled, and 50,548 unigenes were mapped at least in one public database. Of these being annotated unigenes, 15,780 unigenes were differentially expressed early after COR treatment, and 19,824 unigenes were differentially expressed late after COR treatment. At the early stage, 8,646 unigenes were up-regulated, while 7,134 unigenes were down-regulated. At the late stage, the numbers of up- and down-regulated unigenes were 7,711 and 12,113, respectively. The annotation data and gene expression analysis of the differentially expressed unigenes suggest that JA-mediated signalling, Ca2+ signal transduction and the CLAVATA-MAPK-WOX signalling pathway may be involved in regulating secondary laticifer differentiation in rubber trees.

Regulatory Potential of bHLH-Type Transcription Factors on the Road to Rubber Biosynthesis in Hevea brasiliensis

“…Previous reports have suggested the possibility that some TFs participate in promoting laticifer differentiation and rubber biosynthesis by modulating transcription of their target genes [11,14,16]. In this research, upregulated genes at 4 h, 24 h, and 5 d after MeJA treatment include 15, 23, and 6 TF genes, respectively, while downregulated genes include 19, 9, and 12 TF genes, respectively (Table S4).…”

“…It is well-known that application of jasmonate induces laticifer cell differentiation and promotes rubber biosynthesis in H. brasiliensis [12]. Previous works performed transcriptome analyses on rubber trees treated with jasmonate or coronatine, a functional mimic of active jasmonate, and revealed several molecular insights, such as the involvement of some TFs in laticifer differentiation and rubber biosynthesis [13][14][15][16][17]. However, they did not identify any apparent determinants for the biological processes because they have not shown which genes are directly regulated by the TFs.…”

Transcriptional analysis of genes involved in competitive nodulation in Bradyrhizobium diazoefficiens at the presence of soybean root exudates

“…Differentially expressed gene enrichment in the KEGG pathways was carried out by KOBAS software (http://kobas.cbi.pku.edu.cn/home.do). The DEGs that were significantly enriched in GO terms and KEGG pathways were identified after hypergeometric testing (Bonferroni-correction P ≤ 0.05) 85 .…”

Perubahan Histologi dan Fisiologi Latisifer pada Tanaman Karet (Hevea brasiliensis Muell Arg.) yang diberi Asam Jasmonat dan Asam Naftalen Asetat Eksogen

“…Sementara itu asam jasmonat justru memberikan efek yang sebaliknya yaitu menghambat pertumbuhan tebal kulit. JA diketahui lebih berperan dalam diferensiasi latisifer di jaringan kulit tanaman karet (Wu et al 2016 Karakteristik tebal kulit karet yang memiliki korelasi positif terhadap potensi produksi lateks (Daslin et al, 2010). Kulit yang tebal memberikan ruang untuk meningkatnya jumlah latisifer.…”

“…Tanaman dengan kulit yang terlalu tipis tidak diharapkan karena berpotensi besar untuk terjadi pelukaan kambium pada saat penyadapan (Kurnia, 2011 Wijayati et al (2005), JA dan auksin merupakan zat pengatur tumbuh (ZPT) yang menginduksi pertambahan jumlah sel-sel sekretori tanaman. Wu et al (2016), melaporkan aplikasi JA dan perkursor JA (asam linolenat) menginduksi pembentukan baris-baris latisifer pada floem sekunder. Ini membuktikan bahwa laju diferensiasi latisifer dari kambium vaskuler dipengaruhi oleh JA dan prekursor JA.…”