Anguita-Maeso Manuel, Trapero-Casas José Luis, Olivares-García Concepción, Ruano-Rosa David, Palomo-Ríos Elena, Jiménez-Díaz Rafael M, Navas-Cortés Juan A, Landa Blanca B
Institute for Sustainable Agriculture, Spanish National Research Council (Consejo Superior de Investigaciones Científicas), Córdoba, Spain.
Institute for Mediterranean and Subtropical Horticulture "La Mayora" (IHSM-UMA-Consejo Superior de Investigaciones Científicas), Department of Botany and Plant Physiology, University of Malaga, Málaga, Spain.
Front Plant Sci. 2021 Mar 3;12:632689. doi: 10.3389/fpls.2021.632689. eCollection 2021.
Host resistance is the most practical, long-term, and economically efficient disease control measure for Verticillium wilt in olive caused by the xylem-invading fungus (), and it is at the core of the integrated disease management. Plant's microbiome at the site of infection may have an influence on the host reaction to pathogens; however, the role of xylem microbial communities in the olive resistance to has been overlooked and remains unexplored to date. This research was focused on elucidating whether olive propagation may alter the diversity and composition of the xylem-inhabiting microbiome and if those changes may modify the resistance response that a wild olive clone shows to the highly virulent defoliating (D) pathotype of . Results indicated that although there were differences in microbial communities among the different propagation methodologies, most substantial changes occurred when plants were inoculated with , regardless of whether the infection process took place, with a significant increase in the diversity of bacterial communities when the pathogen was present in the soil. Furthermore, it was noticeable that olive plants multiplied under conditions developed a susceptible reaction to D , characterized by severe wilting symptoms and 100% vascular infection. Moreover, those propagated plants showed an altered xylem microbiome with a decrease in total OTU numbers as compared to that of plants multiplied under non-aseptic conditions. Overall, 10 keystone bacterial genera were detected in olive xylem regardless of infection by and the propagation procedure of plants ( vs nursery), with (36.85%), (20.93%), (6.28%), (4.95%), (3.91%), and (3.54%) being the most abundant. spp. appeared as the most predominant bacterial group in micropropagated plants and appeared as a keystone bacterium in inoculated plants irrespective of their propagation process. Our results are the first to show a breakdown of resistance to in a wild olive that potentially may be related to a modification of its xylem microbiome and will help to expand our knowledge of the role of indigenous xylem microbiome on host resistance, which can be of use to fight against main vascular diseases of olive.
宿主抗性是控制由木质部入侵真菌（）引起的油橄榄黄萎病最切实可行、长期且经济高效的病害防治措施，也是综合病害管理的核心。感染部位的植物微生物群可能会影响宿主对病原体的反应；然而，木质部微生物群落在油橄榄对的抗性中的作用一直被忽视，至今仍未得到探索。本研究的重点是阐明油橄榄繁殖是否会改变木质部栖息微生物群的多样性和组成，以及这些变化是否会改变野生油橄榄克隆对高毒力落叶（D）致病型的抗性反应。结果表明，尽管不同繁殖方法之间的微生物群落存在差异，但无论感染过程是否发生，当植物接种时，变化最为显著，当土壤中存在病原体时，细菌群落的多样性显著增加。此外，值得注意的是，在条件下繁殖的油橄榄植株对D表现出易感反应，其特征为严重萎蔫症状和100%的维管束感染。此外，与在非无菌条件下繁殖的植株相比，那些繁殖的植株木质部微生物群发生了改变，总OTU数量减少。总体而言，无论是否感染以及植株的繁殖程序（组培苗与苗圃苗）如何，在油橄榄木质部中均检测到10个关键细菌属，其中（36.85%）、（20.93%）、（6.28%）、（4.95%）、（3.91%）和（3.54%）最为丰富。 spp.在组培苗中是最主要的细菌类群，而无论其繁殖过程如何，在接种植株中均表现为关键细菌。我们的研究结果首次表明，野生油橄榄对的抗性丧失可能与其木质部微生物群的改变有关，这将有助于扩展我们对本土木质部微生物群在宿主抗性中作用的认识，从而有助于防治油橄榄的主要维管束病害。
