Singh Ashish Kumar, Kushwaha Nirbhay, Chakraborty Supriya
Molecular Virology Laboratory, School of Life Sciences, Jawaharlal Nehru University, New Delhi, 110 067, India.
Appl Microbiol Biotechnol. 2016 May;100(9):4035-49. doi: 10.1007/s00253-015-7279-5. Epub 2016 Jan 18.
Chilli (Capsicum sp.) is one of the economically important spice and vegetable crops grown in India and suffers great losses due to the infection of begomoviruses. Conventional breeding approaches have resulted in development of a few cultivars of chilli resistant to begomoviruses. A severe leaf curl disease was observed on one such resistant chilli cultivar (Capsicum annuum cv. Kalyanpur Chanchal) grown in the experimental field of the Jawaharlal Nehru University, New Delhi. Four different viral genomic components namely, Chilli leaf curl virus (DNA A), Tomato leaf curl Bangladesh betasatellite (DNA β), Tomato leaf curl New Delhi virus (DNA A), and Tomato leaf curl Gujarat virus (DNA B) were associated with the severe leaf curl disease. Further, frequent association of these four genomic components was also observed in symptomatic plants of other chilli cultivars (Capsicum annuum cv. Kashi Anmol and Capsicum chinense cv. Bhut Jolokia) grown in the experimental field. Interaction studies among the isolated viral components revealed that Nicotiana benthamiana and chilli plants inoculated with four genomic components of begomoviruses exhibited severe leaf curl disease symptoms. In addition, this synergistic interaction resulted in increased viral DNA accumulation in infected plants. Resistant chilli plants co-inoculated with four genomic components of begomoviruses showed drastic reduction of host basal (ascorbate peroxidase, thionin, polyphenol oxidase) and specific defense-related gene (NBS-LRR) expression. Our results suggested that synergistic interaction among begomoviruses created permissive cellular environment in the resistant chilli plants which leads to breakdown of natural resistance, a phenomenon observed for the first time in chilli.
辣椒（辣椒属）是印度种植的重要经济香料和蔬菜作物之一，因感染双生病毒而遭受巨大损失。传统育种方法已培育出一些抗双生病毒的辣椒品种。在新德里贾瓦哈拉尔·尼赫鲁大学的试验田中种植的一种抗辣椒品种（辣椒属卡利安布尔·钱查尔品种）上观察到一种严重的卷叶病。四种不同的病毒基因组成分，即辣椒卷叶病毒（DNA A）、番茄卷叶孟加拉β卫星（DNA β）、番茄卷叶新德里病毒（DNA A）和番茄卷叶古吉拉特病毒（DNA B）与这种严重的卷叶病有关。此外，在试验田中种植的其他辣椒品种（辣椒属卡什·阿摩尔品种和中国辣椒属布特·乔洛基亚品种）的有症状植株中也经常观察到这四种基因组成分的关联。对分离出的病毒成分进行的相互作用研究表明，接种双生病毒四种基因组成分的本氏烟草和辣椒植株表现出严重的卷叶病症状。此外，这种协同相互作用导致受感染植株中病毒DNA积累增加。与双生病毒四种基因组成分共同接种的抗性辣椒植株显示宿主基础（抗坏血酸过氧化物酶、硫堇、多酚氧化酶）和特定防御相关基因（NBS-LRR）表达大幅降低。我们的结果表明，双生病毒之间的协同相互作用在抗性辣椒植株中创造了允许的细胞环境，导致天然抗性丧失，这是在辣椒中首次观察到的现象。
