Genetic Diversity, Pathogenicity and Pseudorecombination of Cucurbit-Infecting Begomoviruses in Malaysia.

Yu-Jeng Chen,Chung-Cheng Lin,Wen-Shi Tsai,Hsuan-Chun Lai,Zhuan Yi Neoh

doi:10.3390/plants10112396

Yu-Jeng Chen, Chung-Cheng Lin + Show 3 more

Open Access

https://doi.org/10.3390/plants10112396

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Abstract

Cucurbits are important crops in the world. However, leaf curl disease constrains their production. Here, begomovirus diversity and pathogenicity associated with the disease in Malaysia were studied based on 49 begomovirus-detected out of 69 symptomatic plants from seven cucurbit crops in 15 locations during 2016 and 2017. The presence of Squash leaf curl China virus (SLCCNV) and Tomato leaf curl New Delhi virus (ToLCNDV) were confirmed by virus detection by polymerase chain reaction, viral DNA sequence analysis and specific detection of the viral components. ToLCNDV Malaysian isolates were further distinguished into strains A, B, C and D. Virus co-infection was detected in bitter gourd, bottle gourd and squash. Among them, eight bitter gourd samples were detected without SLCCNV DNA-A. However, one bottle gourd and five squash samples were without ToLCNDV DNA-B. Pseudorecombination of ToLCNDV DNA-A and SLCCNV DNA-B was detected in two bitter gourd samples. The pathogenic viruses and pseudorecombinants were confirmed by agroinoculation. The viral DNA-B influencing on symptomology and host range was also confirmed. The results strengthen the epidemic of cucurbit-infecting begomovirus in Malaysia as well as Southeast Asia. Especially, the natural pseudorecombinant of begomovirus that extends host range and causes severe symptom implies a threat to crops.

Highlights

Cucurbits are important economic crops, and their growing acreage has reached 7.89 million hectares with production of more than 238.6 million tons worldwide, withAsian countries being the major contributors [1]
In 2017, begomovirus was detected in 15 out of 16 samples collected from Kuching, Sarawak, Malaysia and in 26 out of 42 samples collected from Kulai, Johor, Malaysia (Table 1)
Squash leaf curl China virus (SLCCNV), Squash leaf curl Philippines virus (SLCuPV) and Tomato leaf curl New Delhi virus (ToLCNDV) are the major disease in China [33], India [14,15,16,17] and Southeast Asia [12,13,34]

Summary

Introduction

Cucurbits are important economic crops, and their growing acreage has reached 7.89 million hectares (ha) with production of more than 238.6 million tons worldwide, withAsian countries being the major contributors [1]. Cucurbits are important economic crops, and their growing acreage has reached 7.89 million hectares (ha) with production of more than 238.6 million tons worldwide, with. Leaf curl disease caused by whitefly-transmitted begomoviruses constrains cucurbit production [2,3,4]. Based on the demarcation criteria of nucleotide sequence identity 91% for the begomovirus species, more than 15 cucurbit-infecting begomovirus species were identified [8]. Tomato leaf curl New Delhi virus (ToLCNDV), Squash leaf curl China virus (SLCCNV) and Squash leaf curl Philippines virus (SLCuPV) were frequently associated with cucurbit leaf curl disease in Asia [9,10,11].

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