Survey of the rubber tree genome reveals a high number of cysteine protease-encoding genes homologous to Arabidopsis SAG12.
Arabidopsis thaliana SAG12, a senescence-specific gene encoding a cysteine protease, is widely used as a molecular marker for the study of leaf senescence. To date, its potential orthologues have been isolated from several plant species such as Brassica napus and Nicotiana tabacum. However, little information is available in rubber tree (Hevea brasiliensis), a rubber-producing plant of the Euphorbiaceae family. This study presents the identification of SAG12-like genes from the rubber tree genome. Results showed that an unexpected high number of 17 rubber orthologues with a single intron were found, contrasting the single copy with two introns in Arabidopsis. The gene expansion was also observed in another two Euphorbiaceae plants, castor bean (Ricinus communis) and physic nut (Jatropha curcas), both of which contain 8 orthologues. In accordance with no occurrence of recent whole-genome duplication (WGD) events, most duplicates in castor and physic nut were resulted from tandem duplications. In contrast, the duplicated HbSAG12H genes were derived from tandem duplications as well as the recent WGD. Expression analysis showed that most HbSAG12H genes were lowly expressed in examined tissues except for root and male flower. Furthermore, HbSAG12H1 exhibits a strictly senescence-associated expression pattern in rubber tree leaves, and thus can be used as a marker gene for the study of senescence mechanism in Hevea.
Danzhou Investigation & Experiment Station of Tropical Crops, Ministry of Agriculture, Rubber Research Institute, Chinese Academy of Tropical Agricultural Sciences, Danzhou, Hainan, P. R. China.
Zhi
http://orcid.org/0000-0003-2881-1932
Z
Zou
Danzhou Investigation & Experiment Station of Tropical Crops, Ministry of Agriculture, Rubber Research Institute, Chinese Academy of Tropical Agricultural Sciences, Danzhou, Hainan, P. R. China.|Crops Research Institute, Fujian Academy of Agricultural Sciences, Fuzhou, Fujian, P. R. China.
Jianting
J
Liu
Danzhou Investigation & Experiment Station of Tropical Crops, Ministry of Agriculture, Rubber Research Institute, Chinese Academy of Tropical Agricultural Sciences, Danzhou, Hainan, P. R. China.
Lifu
L
Yang
Danzhou Investigation & Experiment Station of Tropical Crops, Ministry of Agriculture, Rubber Research Institute, Chinese Academy of Tropical Agricultural Sciences, Danzhou, Hainan, P. R. China.
Guishui
G
Xie
D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000145:classification / Q000235:genetics*; D029681:Arabidopsis Proteins / Q000737:chemistry / Q000235:genetics*; D019295:Computational Biology / Q000379:methods; D017124:Conserved Sequence; D003546:Cysteine Endopeptidases / Q000737:chemistry / Q000235:genetics*; D057056:Cysteine Proteases / Q000737:chemistry / Q000235:genetics*; D018506:Gene Expression Regulation, Plant; D018745:Genome, Plant; D023281:Genomics / Q000379:methods; D028482:Hevea / Q000145:classification / Q000235:genetics*; D005810:Multigene Family; D010802:Phylogeny; D017385:Sequence Homology
D029681:Arabidopsis Proteins; D057056:Cysteine Proteases; C402082:SAG12 protein, Arabidopsis; D003546:Cysteine Endopeptidases