Some ethylene biosynthesis and AP2/ERF genes reveal a specific pattern of expression during somatic embryogenesis in Hevea brasiliensis

Abstract

BackgroundEthylene production and signalling play an important role in somatic embryogenesis, especially for species that are recalcitrant in in vitro culture. The AP2/ERF superfamily has been identified and classified in Hevea brasiliensis. This superfamily includes the ERFs involved in response to ethylene. The relative transcript abundance of ethylene biosynthesis genes and of AP2/ERF genes was analysed during somatic embryogenesis for callus lines with different regeneration potential, in order to identify genes regulated during that process.ResultsThe analysis of relative transcript abundance was carried out by real-time RT-PCR for 142 genes. The transcripts of ERFs from group I, VII and VIII were abundant at all stages of the somatic embryogenesis process. Forty genetic expression markers for callus regeneration capacity were identified. Fourteen markers were found for proliferating calli and 35 markers for calli at the end of the embryogenesis induction phase. Sixteen markers discriminated between normal and abnormal embryos and, lastly, there were 36 markers of conversion into plantlets. A phylogenetic analysis comparing the sequences of the AP2 domains of Hevea and Arabidopsis genes enabled us to predict the function of 13 expression marker genes.ConclusionsThis first characterization of the AP2/ERF superfamily in Hevea revealed dramatic regulation of the expression of AP2/ERF genes during the somatic embryogenesis process. The gene expression markers of proliferating callus capacity to regenerate plants by somatic embryogenesis should make it possible to predict callus lines suitable to be used for multiplication. Further functional characterization of these markers opens up prospects for discovering specific AP2/ERF functions in the Hevea species for which somatic embryogenesis is difficult.

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

“…Firstly, the work has focused in the role of AP2/ERF transcription factors in the developmental aspect of rubber tree. 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.…”

PERKEMBANGAN KULTUR IN VITRO PADA TANAMAN KARET (Hevea brasiliensis, Müell. Arg.) MELALUI EMBRIOGENESIS SOMATIK DI CIRAD PERANCIS

“…se hing g a m e ng ur a ng i r e siko va r ia si somaklonal dan hilangnya kompetensi kalus untuk menginduksi embrio (Piyatrakul et al, 2012;Lardet et al, 2007). Meskipun demikian, berbagai perlakuan kriopreservasi dan pelelehan (thawing) dapat menginduksi stres sel dan mengakibatkan perubahan morfogenik atau genetik kalus.…”

“…Embrio dewasa akan terbentuk setelah delapan minggu inkubasi. Piyatrakul et al (2012) membagi embrio b e r d a s a r k a n m o r f o l o g i d a n mengelompokkannya menjadi tiga kelas. Kelas 1 merupakan embrio normal dengan kualitas baik yang dicirikan dengan adanya satu badan embrionik dan dua kotiledon yang berkembang sempurna (simetri bilateral) (Gambar 4.A).…”

“…Planlet dari embrio normal mempunyai sistem perakaran, batang, dan daun yang berkembang sempurna dalam waktu satu bulan (Gambar 5). Hasil penelitian Piyatrakul et al (2012) Secara teori, teknik ESS dan kriopreservasi bisa digunakan untuk perbanyakan klon-klon yang responsif terhadap ESP untuk menghasilkan bahan tanam dengan kualitas yang baik dan stabil dalam jangka panjang. CIRAD telah berhasil menghasilkan galur kalus teregenerasi CI07060 dari klon PB 260 yang digunakan sebagai galur kontrol dan merupakan cikal bakal galur-galur kalus transgenik untuk menciptakan tanaman karet transgenik.…”

“…Berbagai galur kalus remah di CIRAD pada media EXP untuk induksi embrio: galur kalus embriogenik teregenerasi (A), embriogenik tidak teregenerasi (B), dan non-embriogenik (C) (Sumber: Piyatrakul et al, 2012). , 2007;Montoro et al, 2012a).…”