Abstract
Crop monocropping usually results in an enrichment of soil-borne pathogens in soil. Crop rotation is an environmentally friendly method for controlling soil-borne diseases. Plant rhizosphere microorganisms, especially plant-beneficial microorganisms, play a major role in protecting plants from pathogens, but responses of these microorganisms to crop rotation remain unclear. Here, we evaluated the effects of rotations with Indian mustard (Brassica juncea) and wild rocket (Diplotaxis tenuifolia (L.) DC.) on cucumber Fusarium wilt disease caused by Fusarium oxysporum f.sp. cucumerinum (FOC). Cucumber rhizosphere bacterial community composition was analyzed by high-throughput amplicon sequencing. Bacteria, Pseudomonas spp., 2,4-diacetylphloroglucinol (an antifungal secondary metabolite) producer and FOC abundances were estimated by real-time PCR. Rotations with Indian mustard and wild rocket suppressed cucumber Fusarium wilt disease and cucumber rhizosphere FOC abundance. Crop rotations increased cucumber rhizosphere bacteria, Pseudomonas spp. and 2,4-diacetylphloroglucinol producer abundances. Moreover, crop rotations changed cucumber rhizosphere bacterial community composition and increased bacterial community diversity. However, crop rotations decreased soil inorganic nitrogen content and inhibited cucumber seedling growth. Overall, rotations with Indian mustard and wild rocket suppressed cucumber Fusarium wilt disease, which might be linked to the increased rhizosphere bacterial diversity and abundances of potential plant-beneficial microorganisms (such as Pseudomonas spp. and 2,4-diacetylphloroglucinol producer).
Highlights
Plant soil-borne diseases are a major cause of crop losses and are difficult to control with conventional strategies, such as the use of resistant host cultivars and synthetic fumigants [1]
No difference in cucumber Fusarium wilt disease severity and seedling dry weight was observed between treatments of Indian mustard and wild rocket
Our results showed that rotations with Indian mustard and wild rocket suppressed cucumber Fusarium wilt disease, which was in line with previous studies showing that rotations with Brassicaceae crops can suppress plant soil-borne diseases [21,22,23]
Summary
Plant soil-borne diseases are a major cause of crop losses and are difficult to control with conventional strategies, such as the use of resistant host cultivars and synthetic fumigants [1]. It is generally known that agricultural systems that increase the spatial and temporal plant diversity in the field (e.g., intercropping, crop rotation and use of cover crop or green manure) can help to manage soil fertility, maintain physical soil properties, and prevent the build-up of soil-borne pathogens [1,3,4,5,6,7]. Crop rotation can suppress plant soil-borne diseases through several mechanisms such as interrupting the cycling of pathogens, releasing antifungal chemicals and changing soil microbial communities [3,5,7]. The responses of specific potential plant-beneficial microorganisms and their disease suppressive functional genes to crop rotation remains unclear
Sign-in/Register to view highlights & summary 
Published Version (
Free)
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call