To further develop EST-SSR marker in rubber tree, we assembled the sequences downloaded from NCBI and Malaysia EST databases of rubber tree. By analyzing the assembled 3 733 unigenes, we identified 566 potential SSR sites in this study. That is to say, there was one EST-SSR in every 3.96 kb. The di-nu-cleotide repeat was the most abundant type, fol owed by tri-, hexa-, tetra- and pen-ta-nucleotide repeat. The most common number of repeat units was 5, fol owed by more than 12, 6 and 7. Of 51 SSR motifs identified in this study, di-, tri-, tetra-, penta- and hexa-nucleotide repeats were 6, 26, 5, 3 and 11 types, respectively. The GA/CT di-nucleotide repeat was the most abundant motif, fol owed by TC/AG, AT/TA, CTT/GAA, TTC/AAG and TCT/AGA. In total, 158 new EST-SSRs were developed and amplified with the DNA of RRIM600 as a template. The results showed that the PCR products of 99 EST-SSRs generated clear amplifying bands. The EST-SSR markers developed in this study further enrich the number of molecular marker in rubber tree, and they wil be widely applied in DNA fingerprinting, genetic diversity, marker-assisted selection and genetic mapping, etc.
[Objective]To elucidate the role of ethylene(ET),a latex yield stimulant of the rubber tree,on the sieve tube(ST)transport efficiency of materials(especially sucrose)needed for natural rubber biosynthesis.[Method]Rubber tree seedlings were treated with ET solution or water which was used as a control on the bark,and latex samples and ST tissue samples were collected for proteomic analyses and latex sucrose content determination respectively.[Results]After ET treatment,the sucrose content of the latex was found significantly decreased.A total of 66 ethylene-responsive proteins(ERPs)were distinguished by two-dimensional gel electrophoresis(2-DE),and 54 were successfully identified by MALDI-TOF/TOF and database searching.The majority of these ERPs were involved in carbohydrate transport and metabolic processes in the ST.[Conclusion]Our findings suggest that the application of ET may increase the transport efficiency of the ST and that the application of ET promotes the consumption of energy and sucrose in the ST.
DAI Long-junQIN Yun-xiaYANG HongDENG ZhiSHI Min-jingLIU HuiTANG Chao-rongLI De-jun
