The vein clearing (kokke kandu) disease suspected to be caused by an unknown virus is an important production constraint of cardamom in India. In the present study the causal virus was transmitted from infected to healthy cardamom plants through the aphid, Pentalonia caladii. Small RNA (sRNA) and RNA sequencing (RNA-seq) of the aphid-inoculated plant showed several nucleorhabdovirus-like contigs. The sRNA and RNA-seq results were verified through reverse transcription polymerase chain reaction (RT-PCR) using total RNA from infected plant and primers designed from the contigs. The cloning and sequencing of RT-PCR products resulted in a sequence of 13,392 bases that showed similarities to nucleorhabdoviruses. The sequenced region contained six open reading frames in the order 3’-N-P-P3-M-G-L-5′ and showed nucleotide sequence identities ranging from 37 to 55% with nucleorhabdoviruses indicating its distinct nature for which we propose the name, cardamom vein clearing virus. A reliable RT-PCR and SYBR Green-based real-time RT-PCR assays were developed for the detection of the virus that will aid in the identification and propagation of virus-free cardamom plants.

在印度，怀疑由未知病毒引起的静脉清理（kokke kandu）病是豆蔻的重要生产限制。在本研究中，病原病毒是通过蚜虫Pentalonia caladii从感染的小豆蔻植物传播到健康的小豆蔻植物的。蚜虫接种后的植物的小RNA（sRNA）和RNA测序（RNA-seq）显示出几种类似核病毒的重叠群。sRNA和RNA-seq结果通过逆转录聚合酶链反应（RT-PCR）使用受感染植物的总RNA和重叠群设计的引物进行验证。RT-PCR产物的克隆和测序产生了13,392个碱基的序列，与核糖核酸病毒显示出相似性。测序区域包含6个以3'-NP-P3-MGL-5'顺序排列的开放阅读框，并显示出37％至55％的核苷酸序列与核弹道病毒相同，表明了其独特的性质，我们建议使用豆蔻静脉清除病毒。