Kumari Shweta, Nagendran Krishnan, Rai Awadhesh Bahadur, Singh Bijendra, Rao Govind Pratap, Bertaccini Assunta
ICAR-Indian Institute of Vegetable Research, Varanasi, India.
ICAR-Indian Agricultural Research Institute, New Delhi, India.
Front Microbiol. 2019 Jun 27;10:1349. doi: 10.3389/fmicb.2019.01349. eCollection 2019.
The presence of phytoplasmas and their associated diseases is an emerging threat to vegetable production which leads to severe yield losses worldwide. Phytoplasmas are phloem-limited pleomorphic bacteria lacking the cell wall, mainly transmitted through leafhoppers but also by plant propagation materials and seeds. Phytoplasma diseases of vegetable crops are characterized by symptoms such as little leaves, phyllody, flower virescence, big buds, and witches' brooms. Phytoplasmas enclosed in at least sixteen different ribosomal groups infecting vegetable crops have been reported thus far across the world. The aster yellows phytoplasma group (16SrI) is presently the prevalent, followed by the peanut witches' broom (16SrII). Wide and overlapping crop and non-crop host ranges of phytoplasmas, polyphagous insect vectors, limited availability of resistance sources and unavailability of environmentally safe chemical control measures lead to an arduous effort in the management of these diseases. The most feasible control of vegetable phytoplasma diseases is a consequence of the development and implementation of integrated disease management programs. The availability of molecular tools for phytoplasma identification at the strain level greatly facilitated this kind of approach. It is moreover essential to understand the molecular basis of phytoplasma-vector interaction, epidemiology and other factors involved in disease development in order to reduce the disease outbreaks. Information on the knowledge about the most widespread phytoplasma diseases in vegetable crops is reviewed here in a comprehensive manner.
植原体及其相关病害的出现对蔬菜生产构成了新的威胁，在全球范围内导致了严重的产量损失。植原体是一类局限于韧皮部的多形细菌，无细胞壁，主要通过叶蝉传播，但也可通过植物繁殖材料和种子传播。蔬菜作物的植原体病害具有小叶、叶变、花变绿、大芽和扫帚状丛生等症状。迄今为止，全世界已报道至少有16个不同核糖体组的植原体感染蔬菜作物。目前，翠菊黄化植原体组（16SrI）最为普遍，其次是花生丛枝植原体（16SrII）。植原体广泛且重叠的作物和非作物寄主范围、多食性昆虫介体、抗性资源有限以及缺乏环境安全的化学防治措施，导致这些病害的防治工作艰巨。蔬菜植原体病害最可行的防治方法是制定和实施综合病害管理计划。菌株水平上用于植原体鉴定的分子工具的可用性极大地促进了这种方法。此外，了解植原体与介体相互作用、流行病学以及病害发生的其他因素的分子基础对于减少病害爆发至关重要。本文全面综述了有关蔬菜作物中最普遍的植原体病害的知识信息。
