生防菌AS_(818)抗药性标记株在大豆根际定殖

COLONIZATON OF STREPTOMYCIN RESISTANT RL-4 OF AS_(818) ON SOYBEAN RHIZOSPHERE

通过60 Co 射线 (1 .0× 1 0 4 rad)对生防菌株链霉菌AS81 8孢子悬液 (1 0 6/mL)进行诱变 ,得到抗链霉素 (>5 0μg/mL)突变株 5株。经诱导 ,RL 4抗链霉素水平达到 1 0 0μg/mL。标记株RL 4在 1 %水琼脂 (WA)和无菌土中培养的大豆根际定殖趋势有所不同。RL 4在1 %WA培养的大豆根表的定殖量呈逐步上升趋势。无菌土中种植的大豆根际和根表的检测表明 :RL 4可在无菌土中大豆根际短期定殖 ,在根际第 1周数量降低了 1 0 0倍 ,以后数量开始逐渐上升 ,第 3周达到高峰 ,数量比第 1周增加了 3个数量级 ,但在第 4周其数量又开始下降 ;在根表RL 4数量逐步下降 ,到第 4周已检测不到RL 4的存在。组织印记法检测发现标记株RL 4可以在无菌培养的大豆根表定殖并沿根分布 ,但却不能定殖于根内。

Spore suspension of Streptomyce s griseus AS 818 (10 6/mL)was radiated b y Co 60 -radiation,the radiation dosage was 1×10 4rad.And 5 streptomy cin resis tant mutants (above 50μg/mL) were screened,then the resistant level of mutant RL-4 was induced to 100μg/mL.The number of RL-4 colonizing on soybean roots pl anted on 1% Water agar or in sterile soil was determined.The results showed tha t it could colonize on soybean rhizosphere and rhizoplane for a short period,bu t there is a little difference.When it was examined in 1% Water agar,the numb er of RL-4 raised gradually in soybean rhizoplane in 4 weeks.But when examined in sterile soil,RL-4 reduced about 100 times at the 1 st week,then raised gradually and reached the highest point at the 3 rd week,and decreased aga in at the 4 th week,In the rhizoplane,it reduced gradually from the 1 st week,and couldn't be examined at the 4 th week. Mutant RL-4 couldn't be found in soybean endorhizosphere by tissue printing.