Plants coexist with diverse microbial communities in their leaves (phyllosphere) and roots (rhizosphere), which influence growth, health, and disease resistance. Host genotype, plant compartment, and environmental factors shape these microbiomes, affecting their ability to recruit beneficial microbes or suppress pathogens. Kiwifruit (Actinidia chinensis), a valuable fruit crop, faces severe yield and quality losses from Pseudomonas syringae pv. actinidiae (Psa), a pathogen that spreads rapidly and is hard to eradicate. Current control methods rely on copper-based chemicals and antibiotics, which pose sustainability and resistance concerns. Based on these challenges, there is an urgent need to explore plant–microbe partnerships and identify microbiome-based approaches for enhancing kiwifruit resistance to bacterial canker.
Hefei, China, August 14, 2024 — A research team from Anhui Agricultural University, in collaboration with partners across China, has uncovered how genotype-associated core bacteria strengthen kiwifruit defenses against bacterial canker. Published (DOI: 10.1093/hr/uhae236) in Horticulture Research, the study integrated DNA sequencing, microbial isolation, and disease-resistance tests to compare the microbiomes of resistant and susceptible kiwifruit cultivars. The results show that resistant cultivars maintain more abundant and stable communities of beneficial microbes, particularly in their root zones, and that specific bacterial strains can act as effective biocontrol agents against Psa.
The researchers examined four kiwifruit cultivars—two resistant (“Wanjin” and “Jinyan”) and two susceptible (“Donghong” and “Hongyang”)—sampling leaves, flowers, fruiting branches, roots, and rhizosphere soil. High-throughput 16S rRNA sequencing revealed that plant compartment had the strongest influence on microbiome structure, followed by host genotype. Resistant cultivars, especially “Wanjin,” harbored higher bacterial diversity in belowground niches, enriched with genera known for biocontrol potential, including Pseudomonas, Bacillus, and Streptomyces.
When plants were infected with Psa, susceptible cultivars showed greater disruption in their phyllosphere microbiome, while resistant cultivars maintained a more stable microbial community. Machine learning identified eight bacterial families as biomarkers distinguishing infected from healthy plants. From “Wanjin” roots and rhizosphere, 420 culturable strains were isolated; 58 showed strong antagonism against Psa. Four strains—Pseudomonas sp. R10, Pseudomonas sp. RS54, Stenotrophomonas sp. R31, and Lysobacter sp. R34—significantly reduced disease severity in twig assays. A combined treatment of Pseudomonas sp. R10 and Stenotrophomonas sp. R31 offered the greatest therapeutic benefit, improving disease control by over 60% compared with single-strain treatments.
“Our work demonstrates that disease-resistant kiwifruit cultivars are not only genetically equipped to fight pathogens but also host a supportive microbial community that strengthens their defenses,” said Dr. Lixin Zhang, senior author of the study. “By identifying key bacterial players and their cooperative effects, we can move toward targeted microbiome management as a sustainable alternative to chemical control. This approach could reduce environmental impact while enhancing plant health, offering a new direction for kiwifruit disease management and potentially benefiting other crops facing similar threats.”
The study underscores the potential of using beneficial microbes as living shields against kiwifruit bacterial canker. By integrating microbiome profiling with functional testing, breeders and growers could select cultivars that naturally harbor protective microbial communities or introduce specific beneficial strains into orchards. This microbiome-based strategy could reduce reliance on copper and antibiotics, mitigating chemical residues and resistance development. Beyond kiwifruit, the findings may inspire similar approaches in other fruit crops, leveraging plant–microbe partnerships for long-term resilience. As global agriculture faces increasing disease pressures, harnessing core microbiomes could become a cornerstone of sustainable crop protection.
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References
DOI
10.1093/hr/uhae236
Original Source URL
https://doi.org/10.1093/hr/uhae236
Funding information
This study was supported by the National Key R&D Program of China (2022YFD1400200), the National Natural Science Foundation of China (32072378, 32302461), the Natural Science Key Research Project of Colleges and Universities in Anhui Province (2023AH050996), the Development Fund for Talent Personnel of Anhui Agricultural University (rc342216), and the Undergraduate Innovation and Entrepreneurship Training Program of Anhui province (S202310364172).
About Horticulture Research
Horticulture Research is an open access journal of Nanjing Agricultural University and ranked number one in the Horticulture category of the Journal Citation Reports ™ from Clarivate, 2023. The journal is committed to publishing original research articles, reviews, perspectives, comments, correspondence articles and letters to the editor related to all major horticultural plants and disciplines, including biotechnology, breeding, cellular and molecular biology, evolution, genetics, inter-species interactions, physiology, and the origination and domestication of crops.