The Effect of Rotating Apple Rootstock Genotypes on Apple Replant Disease and Rhizosphere Microbiome
The Effect of Rotating Apple Rootstock Genotypes on Apple Replant Disease and Rhizosphere Microbiome
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DOI：
10.1094/pbiomes-03-19-0018-r
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发表时间：
2019-01-01
影响因子：
4.4
通讯作者：
Xu, Xiangming
中科院分区：
文献类型：
--
作者：
Deakin, Greg;Fernandez-Fernandez, Felicidad;Xu, Xiangming
苹果（Malus pumila）在同一地点连续种植园，以前种植相同或密切相关的物种，导致建立不良，生长活力降低，随后作物损失;这种现象被称为苹果再植病（ARD）。由于（i）广谱土壤熏蒸剂的使用受到限制，（ii）ARD的假定病原体可能具有场地特异性，以及（iii）一个场地可能存在不止一种病原体，因此ARD的管理是一个持续的挑战。我们在两个果园地点进行了试验研究，以调查砧木基因型对苹果树建立的继承效应，有三个具体目标：（i）如果重新种植与前一棵相同的砧木，新种植的苹果树的ARD是否更严重，（ii）树木在过道中的生长是否比在原始树站中的生长更好，以及（iii）砧木基因型与根际微生物组在ARD方面的关联程度。树木生长和根际微生物组进行了评估，在30个月内重新种植。在一个果园中，重新种植具有与先前不同的砧木基因型的树木可以有效地减少ARD的发展，对ARD的易感性可能是遗传控制的，并且在先前的草过道中重新种植树木可以减少ARD的发展。然而，在另一个果园中得到了相反的结果，可能是由于草通道中缺乏杂草管理影响了草通道中的树木建立。与特定砧木基因型相关的根际微生物群在再植后7个月内达到稳定状态。一个丛枝菌根真菌操作分类单位（OTU）与ARD树的丰度降低;然而，许多其他与ARD相关的OTU不能被鉴定为低分类等级，因此它们的作用不能很容易地解释。总之，重新种植与之前不同的砧木的树木可以减少ARD的发展。然而，在采用这种策略时，需要考虑砧木基因型之间遗传关系的程度。
Continuous plantation of apple trees (Malus pumila) at the same sites where the same or a closely related species were grown previously leads to poor establishment, reduced growth vigor, and subsequent crop losses; this phenomenon is termed apple replant disease (ARD). Management of ARD is a continual challenge due to (i) restrictions on the use of broad-spectrum soil fumigants, (ii) putative causal agents of ARD can be site-specific, and (iii) more than one causal agent can be present at a site. We conducted an experimental study at two orchard sites to investigate the succession effect of rootstock genotypes on apple tree establishment with three specific objectives: (i) whether ARD in newly planted apple trees is more severe if the same rootstock as the previous one is replanted, (ii) whether trees develop better in the aisle than in original tree stations, and (iii) the extent of association of rootstock genotypes with rhizosphere microbiome in relation to ARD. Tree growth and rhizosphere microbiome were assessed within 30 months of replanting. In one orchard, replanting trees with a rootstock genotype different from the previous one can be effective in reducing ARD development, susceptibility to ARD is likely to be genetically controlled, and replanting trees in the previous grass aisle can reduce ARD development. However, the opposite results were obtained in the other orchard, possibly due to the lack of weed management in the grass aisle affecting tree establishment in the grass aisle. Rhizosphere microbiota associated with specific rootstock genotypes reached a stable state within 7 months of replanting. An arbuscular mycorrhizal fungi operational taxonomic unit (OTU) had reduced abundance with ARD trees; however many other OTUs associated with ARD cannot be identified to low taxonomic ranks and hence their roles cannot be easily interpreted. In conclusion, replanting trees with rootstocks that are genetically differently from the previous one can reduce ARD development. However, in adopting this strategy, the extent of genetic relationships among rootstock genotypes needs to be considered.