Biocontrol Potential of a Novel Endophytic Bacterium From Mulberry (Morus) Tree
Biocontrol Potential of a Novel Endophytic Bacterium From Mulberry (Morus) Tree
复制标题
DOI：
10.3389/fbioe.2019.00488
复制
发表时间：
2020-01
影响因子：
5.7
通讯作者：
Sen Xie;M. Vallet;Chao Sun;Maritta Kunert;A. David;Xiancui Zhang;Bosheng Chen;Xingmeng Lu
中科院分区：
文献类型：
--
作者：
Sen Xie;M. Vallet;Chao Sun;Maritta Kunert;A. David;Xiancui Zhang;Bosheng Chen;Xingmeng Lu
桑葚（Morus）是一种重要的木本经济树种，在养蚕业、饲料业和医药业等方面都有重要的应用价值。然而，这种阔叶树正面临着从植物病原体到害虫的多重威胁。在这里，革兰氏阳性，内生孢子形成细菌（ZJU1）经常从健康的桑葚植物筛选叶面内生菌表现出对病原体和害虫的拮抗作用。全基因组测序和注释导致基因组大小为4.06 Mb，并将该细菌分类为一种新的解淀粉芽孢杆菌菌株，该菌株很少从树叶中鉴定出来。结合传统的天然产物化学，活性生物测定和高分辨率质谱的综合方法证实，菌株ZJU1使用包括肽和挥发性有机化合物在内的抗菌剂的混合物来对抗灰葡萄孢（Botrytis cinerea），灰葡萄孢是一种引起桑葚灰霉病的主要植物病原真菌。我们表明，在田间条件下，用ZJU1接种无内生菌的植物显著降低了叶片坏死和死亡率。除了内生菌与叶面病原菌的直接相互作用外，植物体内研究表明，内生菌的接种还诱导植物系统防御，包括桑葚抗病基因的高表达水平。此外，当将ZJU 1施用于通性食草动物斜纹夜蛾时，足以将害虫存活率降低到50%以下。一种以前未发现的晶体毒素（Cry10Aa）可能有助于对臭名昭著的鳞翅目害虫产生这种杀虫效果。这些独特的特征清楚地表明，B。ZJU1在生物防治应用的成功策略的开发上是有希望的。因此，寻找新的植物有益微生物和工程微生物组对于可持续地改善植物性能具有重要意义。
Mulberry (Morus) is an economically important woody tree that is suitable for use in sericulture as forage and in medicine. However, this broad-leaved tree is facing multiple threats ranging from phytopathogens to insect pests. Here, a Gram-positive, endospore-forming bacterium (ZJU1) was frequently isolated from healthy mulberry plants by screening for foliar endophytes showing antagonism against pathogens and pests. Whole-genome sequencing and annotation resulted in a genome size of 4.06 Mb and classified the bacterium as a novel strain of Bacillus amyloliquefaciens that has rarely been identified from tree leaves. An integrative approach combining traditional natural product chemistry, activity bioassays, and high-resolution mass spectrometry confirmed that strain ZJU1 uses a blend of antimicrobials including peptides and volatile organic compounds to oppose Botrytis cinerea, a major phytopathogenic fungus causing mulberry gray mold disease. We showed that the inoculation of endophyte-free plants with ZJU1 significantly decreased both leaf necrosis and mortality under field conditions. In addition to the direct interactions of endophytes with foliar pathogens, in planta studies suggested that the inoculation of endophytes also induced plant systemic defense, including high expression levels of mulberry disease resistance genes. Moreover, when applied to the generalist herbivore Spodoptera litura, ZJU1 was sufficient to reduce the pest survival rate below 50%. A previously undiscovered crystal toxin (Cry10Aa) could contribute to this insecticidal effect against notorious lepidopteran pests. These unique traits clearly demonstrate that B. amyloliquefaciens ZJU1 is promising for the development of successful strategies for biocontrol applications. The search for new plant-beneficial microbes and engineering microbiomes is therefore of great significance for sustainably improving plant performance.