Identification and characterization of the MADS-box genes highly expressed in the laticifer cells of Hevea brasiliensis

Ying Wang,Di-Feng Zhan,Hui-Liang Li,Jia-Hong Zhu,Dong Guo,Shi-Qing Peng

doi:10.1038/s41598-019-48958-9

Ying Wang, Di-Feng Zhan + Show 4 more

Open Access

https://doi.org/10.1038/s41598-019-48958-9

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Abstract

MADS-box transcription factors possess many functions in plant reproduction and development. However, few MADS-box genes related to secondary metabolites regulation have been identified. In Hevea brasiliensis, natural rubber is a representative cis-polyisoprenoids in secondary metabolism which occurs in the rubber laticifer cells, the molecular regulation basis of natural rubber biosynthesis is not clear. Here, a total of 24 MADS-box genes including 4 type I MADS-box genes and 20 type II MADS-box genes were identified in the transcriptome of rubber tree latex. The phylogenetic analysis was performed to clarify the evolutionary relationships of all the 24 rubber tree MADS-box proteins with MADS-box transcription factors from Arabidopsis thaliana and Oryza sativa. Four type I MADS-box genes were subdivided into Mα (3 genes) and Mβ (1 gene). Twenty type II MADS-box genes were subclassified into MIKC* (8 genes) and MIKCc (12 genes). Eight MADS-box genes (HblMADS3, 5, 6, 7, 9, 13, 23, 24) were predominant expression in laticifers. ABA up-regulated the expression of HblMADS9, and the expression of HblMADS3, HblMADS5, HblMADS24 were up-regulated by MeJA. The function of HblMADS24 was elucidated. HblMADS24 bound HbFPS1 promoter in yeast and HblMADS24 activated HbFPS1 promoter in tobacco plants. Moreover, we proposed that HblMADS24 is a transcription activator of HbFPS1 which taking part in natural rubber biosynthesis.

Highlights

MADS-box transcription factors play an indispensable role in plant growth and development[1,2,3,4]
A total of 36 MADS-box unigenes were obtained by scanning the H. brasiliensis latex transcriptome database
These MADS-box unigenes were used as queries in BLAST against the local H. brasiliensis genome database

Summary

Introduction

MADS-box transcription factors play an indispensable role in plant growth and development[1,2,3,4]. MADS-box genes possess many functions in determination of floral organ identity, floral transition, flowering time determination[3,5,6,7,8,9,10], embryo development and seed pigmentation[11], fruit ripening regulation[12]. The type II lineage includes three other domains: the Keratin-like (K) domain, the Intervening (I) domain and the C-terminal (C) region[22,23,24] In dicot plants such as Arabidopsis, the floral homeotic genes were divided into ABCDE-classes based on function[25,26,27]. HbFPS2 and HbFPS3 have no cell-type specific expression, and they are likely to act as housekeeping nature to involve in isoprenoid biosynthesis[43]. Three MADS-box genes of H. brasiliensis were identified They were differentially expressed in the laticifer cells[45].

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