title: Function of Hevea brasiliensis NAC1 in dehydration-induced laticifer differentiation and latex biosynthesis.
abstract: HbNAC1 is a transcription factor in rubber plants whose expression is induced by dehydration, leading to latex biosynthesis. Laticifer is a special tissue in Hevea brasiliensis where natural rubber is biosynthesized and accumulated. In young stems of epicormic shoots, the differentiation of secondary laticifers can be induced by wounding, which can be prevented when the wounding site is wrapped. Using this system, differentially expressed genes were screened by suppression subtractive hybridization (SSH) and macroarray analyses. This led to the identification of several dehydration-related genes that could be involved in laticifer differentiation and/or latex biosynthesis, including a NAC transcription factor (termed as HbNAC1). Tissue sections confirmed that local tissue dehydration was a key signal for laticifer differentiation. HbNAC1 was localized at the nucleus and showed strong transcriptional activity in yeast, suggesting that HbNAC1 is a transcription factor. Furthermore, HbNAC1 was found to bind to the cis-element CACG in the promoter region of the gene encoding the small rubber particle protein (SRPP). Transgenic experiments also confirmed that HbNAC1 interacted with the SRPP promoter when co-expressed, and enhanced expression of the reporter gene β-glucuronidase occurred in planta. In addition, overexpression of HbNAC1 in tobacco plants conferred drought tolerance. Together, the data suggest that HbNAC1 might be involved in dehydration-induced laticifer differentiation and latex biosynthesis.
authors.affiliation: Hainan Key Laboratory for Sustainable Utilization of Tropical Bioresources, College of Agriculture, Hainan University, Haikou, 570228, People's Republic of China.
authors.forename: Yuxin
authors.initials: Y
authors.lastname: Cao
authors.affiliation: Hainan Key Laboratory for Sustainable Utilization of Tropical Bioresources, College of Agriculture, Hainan University, Haikou, 570228, People's Republic of China.
authors.forename: Jinling
authors.initials: J
authors.lastname: Zhai
authors.affiliation: Hainan Key Laboratory for Sustainable Utilization of Tropical Bioresources, College of Agriculture, Hainan University, Haikou, 570228, People's Republic of China.
authors.forename: Qichao
authors.initials: Q
authors.lastname: Wang
authors.affiliation: Hainan Key Laboratory for Sustainable Utilization of Tropical Bioresources, College of Agriculture, Hainan University, Haikou, 570228, People's Republic of China.
authors.forename: Hongmei
authors.initials: H
authors.lastname: Yuan
authors.affiliation: Hainan Key Laboratory for Sustainable Utilization of Tropical Bioresources, College of Agriculture, Hainan University, Haikou, 570228, People's Republic of China. xihuang@hainu.edu.cn.
authors.forename: Xi
authors.initials: X
authors.lastname: Huang
mesh_terms: D000222:Adaptation, Physiological / Q000235:genetics; D001483:Base Sequence; D002454:Cell Differentiation; D003681:Dehydration; D055864:Droughts; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant; D028482:Hevea / Q000166:cytology* / Q000235:genetics; D007840:Latex / Q000096:biosynthesis*; D024301:Plant Bark / Q000166:cytology; D010940:Plant Proteins / Q000378:metabolism*; D030821:Plants, Genetically Modified; D011401:Promoter Regions, Genetic; D011485:Protein Binding; D015203:Reproducibility of Results; D012441:Saccharomyces cerevisiae / Q000378:metabolism; D013312:Stress, Physiological; D013347:Subcellular Fractions / Q000378:metabolism; D066251:Subtractive Hybridization Techniques; D014026:Nicotiana / Q000235:genetics; D015533:Transcriptional Activation / Q000235:genetics
chemical_list: D007840:Latex; D010940:Plant Proteins
keywords: Dehydration; HbNAC1; HbSRPP; Hevea brasiliensis; Laticifer differentiation