Biological characteristics and genetic diversity of wild Ganoderma lucidum in Guangxi

【Objective】In order to lay a theoretical foundation for the selection of wild Ganoderma lucidum resources development,utilization and breeding of new varieties in Guangxi,the biological characteristics and genetic diversity of G. lucidum strains collected in Guangxi were analyzed.【Method】 The optimum growth conditions of 19 wild G. lucidum strains collected in Guangxi and 5 cultivated G. lucidum strains collected from out of Guangxi were determined by comparing the mycelial growth rate at different growth temperatures,pH values, carbon sources and nitrogen sources. Genetic diversity analysis of each stain was carried out using SSR molecular markers.【Result】 The mycelium of the 24 collected G. lucidum strains could grow at 15-30℃,but stopped growth at 10℃. The mycelial growth rate was the slowest at 15℃ for all strains(below 1.26 mm/d);the growth rate increased at 20℃ and 25℃,ranging from 1.93 to 3.93 mm/d and 4.02 to 5.92 mm/d respectively;the mycelial growth rate was the fastest at 30℃(higher than 6.17 mm/d for all strains). Only 2 out of the 24 strains could survive at 35℃. The optimal growth pH for 8 strains were ≤ 5.0,and ≥ 8.0 for the rest 16 strains. Fructose was the optimal carbon source for 13 strains,sucrose for 6 strains,glucose for 3 strains,and fructose and sucrose for the last two strains. Lactose,maltose and starch were not suitable carbon sources for the tested G. lucidum strains. Yeast powder was the optimal nitrogen source for 15 strains,ammonium for 5 strains,ammonium nitrate for 2 strains,ammonium sulfate for 1 strain,beef extract for 2 strains,and potassium nitrate and peptone for 1 strain. The optimal nitrogen sources for RSLZ-1901 were yeast powder,ammonium nitrate and ammonium sulfate. The optimal nitrogen sources for CLZ-119 were yeast powder and peptone. Urea was not suitable nitrogen source for G. lucidum. The level of genetic similarities among the 24 strains were 0.49-0.93. At a genetic similarity level of 0.68,the 24 G. lucidum strains could be divided into 5 groups, indicating great genetic diversities among them.【Conclusion】 The growth rate and vigor of mycelium of the selected G. lucidum strains are positively correlated with temperature,and the optimal growth temperature is 30℃. Eight strains have strong acid resistance, and 16 strains have strong alkali resistance. The most suitable carbon sources include fructose,sucrose,and glucose;the best nitrogen sources are yeast powder,ammonium nitrate,ammonium sulfate,beef extract,potassium nitrate and peptone. These 24 selected G. lucidum strains from Guangxi show great genetic diversities and significantly different biological characteristics. The results indicate that the genetic diversity of G. lucidum strains is rich and can be used for germplasm innovation and variety breeding in Guangxi.