Cook Chris, Magan Naresh, Xu Xiangming
NIAB, East Malling, Kent, UK.
Applied Mycology Group, Environment and AgriFood Theme, Cranfield University, Cranfield, Bedfordshire, UK.
Phytopathol Res. 2023;5(1):28. doi: 10.1186/s42483-023-00184-y. Epub 2023 Jul 4.
Apple rootstock genotypes confer different levels of tolerance to apple replant disease (ARD) and vigour to a newly replanted apple tree. A hybrid management system of rotating the rootstock genotype planted between successive generations and inter-row planting in the alleyways of orchards may minimise the severity of ARD symptoms. High-throughput sequencing of the fungal ITS and bacterial 16S rDNA regions was used to investigate the diversity, and differential taxa present in soils displaying symptoms of ARD. Candidate pathogens and beneficial microorganisms were correlated with the above-ground establishment of each rootstock genotype in a UK cider orchard. Our results suggest that the same rootstock or rootstock with closely related parentage to the previous rootstock had more severe ARD symptoms. Planting in the alleyway appeared an effective strategy to minimise the severity of symptoms irrespective of rootstock genotype. The planting location effect had a higher contribution to the variation in the rhizosphere microbiome than that of the rootstock genotype. No predicted causal agents for ARD could be identified to a taxonomic level to predict their function but two species associated with mycorrhizae, and were identified as inversely correlated with ARD severity and could be candidate beneficial species for apple, warranting further investigation and research. Our findings suggest that planting in the alleyways and planting rootstocks genetically dissimilar to the previously planted rootstock can be beneficial for tree establishment. We have also identified species inversely associated with ARD severity, making candidates for future research to test the antagonistic effect of the species against ARD pathogens in apple roots.
The online version contains supplementary material available at 10.1186/s42483-023-00184-y.
苹果砧木基因型对苹果再植病（ARD）的耐受水平不同，对新种植的苹果树活力影响也不同。在果园行间通道中，采用连续几代轮换种植砧木基因型和间行种植的混合管理系统，可能会使ARD症状的严重程度降至最低。利用真菌ITS和细菌16S rDNA区域的高通量测序来研究显示ARD症状的土壤中的多样性和差异分类群。在英国一个苹果酒果园中，将候选病原体和有益微生物与每种砧木基因型的地上植株建立情况相关联。我们的结果表明，相同的砧木或与前一种砧木亲缘关系密切的砧木会出现更严重的ARD症状。无论砧木基因型如何，在行间通道种植似乎是一种减轻症状严重程度的有效策略。种植位置效应比砧木基因型对根际微生物组变异的贡献更大。在分类水平上无法确定ARD的预测致病因子以预测其功能，但鉴定出两种与菌根相关的物种，它们与ARD严重程度呈负相关，可能是苹果的候选有益物种，值得进一步研究。我们的研究结果表明，在行间通道种植以及种植与先前种植的砧木基因不同的砧木，可能有利于树木的生长。我们还鉴定出与ARD严重程度呈负相关的物种，为未来研究测试这些物种对苹果根中ARD病原体的拮抗作用提供了候选对象。
在线版本包含可在10.1186/s42483-023-00184-y获取的补充材料。
