The proteins on rubber particles of Hevea brasiliensis play key roles in a series of reactions of rubber biosynthesis. They directly determine the number and size of rubber molecules, thus affecting the yield and quality of natural rubber. Small rubber particle protein (SRPP) is the second highest abundance protein in rubber particles following after the rubber elongation factor (REF), which is closely related to rubber particle development and rubber biosynthesis. At present, it is known that there are many SRPP family proteins on rubber particles, but the functions of most SRPP family proteins have not been identified. SRPP may function by interacting with other rubber particle proteins. To screen the interaction protein of HbSRPP7, a normalized H. brasiliensis latex cDNA library was constructed based on the membrane yeast two-hybrid (MYTH) system. The capacity of the cDNA library was 1.5×107 CFU, the average library recombination rate was about 100%, and the average amplification sizes of insert fragments in the cDNA library were above 1500 bp. The pBT3STE-SRPP7 and pBT3SUC-SRPP7 bait vectors were constructed and confirmed that they could be correctly expressed in the NMY32 yeast strain without self-activating activity. The latex MYTH cDNA library was screened using the bait plasmid pBT3STE-SRPP7, and 21 candidate proteins of HbSRPP7 were obtained, including three REF family proteins (HbREF1, HbREF3, and HbREF8), two SRPP family proteins (HbSRPP1 and HbSRPP2), two reactive oxygen species scavenging-related proteins (thioredoxin H-type-like and L-ascorbate peroxidase 2), and five stress-related proteins (high mobility group B protein 2-like, RPM1-interacting protein 4-like, stress-related protein-like, salt stress-induced hydrophobic peptide ESI3-like and F-box/kelch-repeat protein). It is shown that HbSRPP7 may participate in rubber biosynthesis through interaction with the rubber particle proteins related to rubber biosynthesis. In addition, HbSRPP7 may also participate in the regulation of rubber biosynthesis on rubber particles by interacting with biotic and abiotic stress-related proteins and responding to biotic and abiotic stress signals in laticiferous cells of H. brasiliensis. The research results are helpful to understand the function of SRPP family proteins and lay a foundation for revealing the composition of protein complexes involved in rubber biosynthesis on rubber particles and elucidating the molecular mechanism of rubber biosynthesis and its regulation.
| 科 Family | 属数 Number of genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) | 属 Genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) |
|---|---|---|---|---|---|---|
| 鹅膏菌科Amanitaceae | 2 | 11 | 5.26 | 鹅膏菌属 Amanita | 10 | 4.78 |
| 小菇科 Mycenaceae | 2 | 12 | 5.74 | 丝盖伞属 Inocybe | 5 | 2.39 |
| 多孔菌科 Polyporaceae | 8 | 14 | 6.70 | 蜡蘑属 Laccaria | 5 | 2.39 |
| 红菇科 Russulaceae | 3 | 23 | 11.00 | 小皮伞属 Marasmius | 6 | 2.87 |
| 小菇属 Mycena | 11 | 5.26 | ||||
| 光柄菇属 Pluteus | 5 | 2.39 | ||||
| 红菇属 Russula | 17 | 8.13 | ||||
| 栓菌属 Trametes | 5 | 2.39 |