Identification of Begomoviruses from Three Cryptic Species of Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae) in Nepal

Abstract

The Bemisia tabaci species complex consists of at least 44 cryptic species, which are potential vectors of approximately 320 begomovirus species, most of which are significant plant viruses. However, the relationship of begomovirus transmission through vectors at the cryptic species level is uncertain. In our previous study, three cryptic species (Asia I, Asia II 1, and Asia II 5) of B. tabaci were identified from 76 B. tabaci samples collected across 23 districts in Nepal. Using the same individuals we identified seven different begomovirus species (Squash leaf curl China virus [SLCCNV], Tomato leaf curl New Delhi virus [ToLCNDV], Okra enation leaf curl virus [OELCuV], Synedrella leaf curl virus [SyLCV], Tomato leaf curl Kerala virus [ToLCKeV], Ageratum enation virus [AEV], and Tomato leaf curl Karnataka virus [ToLCKV]) by PCR using universal begomovirus primers. The begomoviruses were detected in 55.26% of whitefly samples, and SLCCNV was the most prevalent species (27.63%). Among the three cryptic species of B. tabaci, the virus detection rate was highest in Asia I (60%), followed by Asia II 1 (58.82%) and Asia II 5 (53.06%). Most viruses were detected in all three species, but AEV and ToLCKV were found only in Asia I and Asia II 1, respectively. Geographic analysis showed that SLCCNV was distributed in the whole country, which is similar to the distribution of the Asia II 5 species, but OELCuV and SyLCV were detected only in the middle region of Nepal. Our results provide important information on the begomovirus profile in Nepal which can be beneficial for plant virus risk assessment and develop the management strategies to reduce the damage of whitefly transmitted viruses.

Mitochondrial Genetic Diversity of Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae) Associated with Cassava in Lao PDR

“…Whiteflies are vectors for at least 320 species of plant viruses belonging to the genera Begomovirus , Carlavirus , Crinivirus , Ipomovirus , Polerovirus and Torradovirus [ 14 , 15 , 16 , 17 ]. Notably, the whitefly species Bemisia tabaci is the sole vector of begomoviruses [ 18 , 19 ] and is considered a complex of at least 44 reproductively isolated but morphologically indistinguishable cryptic species [ 20 ].…”

“…In several Asian countries such as Bangladesh China, Nepal, Thailand, Malaysia and Vietnam, different studies using mtCOI have identified B. tabaci species diversity and their potential as virus vectors [ 17 , 28 , 29 , 30 , 31 , 32 ]. The relevance of characterizing B. tabaci diversity has increased in SEA due to increasing importance of cassava and the recent introduction of CMD in this region [ 3 , 5 ].…”

First report of Cucurbit Chlorotic Yellows Virus (CCYV) and Tomato Leaf Curl New Delhi Virus (ToLCNDV) in Algeria and lack of evidence for seed transmission of ToLCNDV in melon and pumpkin.

“…Recently, in Pakistan it has been identified infecting potato (Hameed et al, 2017), soybean (Glycine max L) and cotton (Gossypium hirsutum L.) and in Sri Lanka in bitter gourd, ridge gourd (Luffa acutangular L.), pumpkin and cucumber (Bandaranayake et al, 2014). ToLCNDV was identified in the Seychelles Islands in tomato (Scussel et al, 2018) and more recently in Nepal in three cryptic species of Bemisia tabaci found in Cucurbitaceae and Solanaceae host plants (Acharya et al, 2021), and in China infecting tomato(Figure 6) (Li et al, 2022).…”