Effect of Streptomyces rochei D74 on sunflower, Orobanche cumana, and their rhizosphere microorganisms

Abstract:

[Objective] To study the role of Streptomyces rochei D74 in promoting sunflower growth and inhibiting Orobanche cumana parasitism, and the effect on rhizosphere microorganisms. [Methods] We developed a sunflower-O. cumana-S. rochei D74 co-culture system to observe the effect of D74 on the parasitism of O. cumana. Through field experiment, we observed the influence of D74 on physiological indexes of sunflower and the number of epigaeous O. cumana, and measured the yield indexes of sunflower to evaluate the influence of D74 on quality and yield of sunflower kernels. High-throughput sequencing of 16S rRNA genes and traditional microbial culture method were used to explore the effect of D74 on microbial community structure in sunflower rhizosphere. [Results] D74 promoted the growth of sunflower, as manifested by the increase (P<0.05) in stem weight (by 37%-40%) and disk weight (by 21%-37%), and inhibited (P<0.05) the seedling emergence of 28%-46% O. cumana. In addition, it raised the crude protein content in sunflower kernels by 5%-9%, percentage of large kernels by 66% (P<0.05), and 100-grain weight by 8%-18%. In the field, D74 elevated the yield by about 30% (P<0.05), which has far-reaching significance for improving farmers’ economic returns. The sunflower rhizosphere microbial community was significantly affected by D74 which regulated the number of beneficial microorganisms. [Conclusion] D74 can significantly reduce the number of O. cumana in sunflower rhizosphere, promote the growth of flower discs, and increase the large kernels, which should be further applied and promoted.