Guangdong Geolong Biotechnology Co. Ltd.

Fusarium wilt of banana is considered one of the most destructive plant diseases. Bacillus subtilis R31 and TR21, isolated from Dendrobium sp. leaves, exhibit different phytobeneficial effects on banana Fusarium wilt bio-controlling. Here, we performed genome sequencing and comparative genomics analysis of R31 and TR21 to enhance our understanding of the different phytobeneficial traits. These results revealed that the strain-specific genes of R31 involved in sporulation, quorum sensing, and antibiotic synthesis allow R31 to present a better capacity of sporulation, rhizosphere adaptation, and quorum sensing than TR21. Selective pressure analysis indicated that the glycosylase and endo-alpha-(1- > 5)-L-arabinanase genes were strong positive selected, which may contribute to the TR21 to colonize well in banana's vascular bundles. Altogether, our findings presented here should advance further agricultural application of R31 and TR21 as two promising resources of plant growth promotion and biological control via genetic engineering.

Fusarium wilt is a devastating soil-borne disease caused mainly by highly host-specific formae speciales of Fusarium oxysporum. Antagonistic microorganisms play a very important role in Fusarium wilt control, and the isolation of potential biocontrol strains is becoming more and more important. We isolated a bacterial strain (SEM-9) from the high-temperature stage of silkworm excrement composting, which had a marked ability to solubilize phosphorus, promote the growth and increase the yield of the small Chinese cabbage, and which also exhibited considerable antagonistic effect towards Fusarium sambucinum and other fungi. The result of physiological and biochemical analyses, as well as genome sequencing, showed that SEM-9 was a strain of Bacillus subtilis. Through genome annotation and analysis, it was found that SEM-9 contained genes related to the regulation of biofilm formation, which may play an important role in colonization, and gene clusters encoding the biosynthesis of antimicrobials, such as surfactin, bacilysin, fengycin, and subtilosin-A. The production of such antifungal compounds may constitute the basis of the mode-of-action of SEM-9 against Fusarium spp. These data suggested that the SEM-9 strain has potential as both a biofertilizer and a biocontrol agent, with the potential to manage Fusarium wilt disease in crops.

Soil compaction and salinization were caused by successive cropping, excessive chem. fertilizer application and unscientific pesticide application.Therefore, the soil-borne diseases were aggravated, the living environment of beneficial rhizospheric microorganisms were destroyed, the soil ecol. balance was broken, and the crop growth was restricted.If agricultural production was carried out on this type of soil, soil deterioration would become more serious.Consequently, plant diseases and pests were exacerbated year by year, and the crop yields decreased or even lost.The polluted ecol. environment could even affect the survival and development of mankind.In southern China, soil acidification, one of the severest soil degradation, was a necessitated problem urgently need to be solved at present.A pot culture experiment was conducted to study the effect of soil amendments on acid soil and the growth of cowpeas.It covered 2 continuous cropping seasons of cowpea ( Vigna unguiculata).The soil amendments were applied in the first growing season, while no soil amendment was used for the second one.Results showed that: (1) When appropriate soil amendment was applied on acid soil, which could be improved.Soil pH and organic matter could be increased, crop growth would be promoted, and crop yield would be increased.(2) In this study, silkworm excrement soil amendment (silkworm excrement 50%, shell powder 40%, magnesium oxide10%) was selected as the optimal soil amendment, which made soil pH rise by 0.77, soil organic matter content increase by 6.49%, and cowpea yield increase by 125.99%.