Analysis of an isolate of Mungbean yellow mosaic virus (MYMV) with a highly variable DNA B component

Abstract

One DNA A (KA30) and five different DNA B components (KA21, KA22, KA27, KA28 and KA34) of a geminivirus, Mungbean yellow mosaic virus-Vigna (MYMV-Vig) were cloned from a pooled sample of field-infected Vigna mungo plants from Vamban, South India. MYMV-Vig DNA A (KA30) and one of the DNA B components (KA27) exhibited 97% and 95% sequence identities, respectively, to those of MYMV reported from Thailand. However, the DNA B components KA21, KA22, KA28 and KA34 exhibited only 71 to 72% sequence identity to MYMV DNA B. Co-existence of multiple DNA B components in field-infected V. mungo was proved by Southern and PCR analyses. Each of the five DNA B components was infective together with the DNA A upon agroinoculation. Agroinoculation with mixed cultures of Agrobacterium with partial dimers of DNA A and all five DNA Bs proved that all five DNA B components can co-infect a single V. mungo plant.

Identification of mungbean lines with tolerance or resistance to yellow mosaic in fields in India where different begomovirus species and different Bemisia tabaci cryptic species predominate

“…Similarly, only strains most similar to MYMV-Vigna were detected in V. radiata and V. mungo in Southern India, and this is as was reported for Vamban (Tamil Nadu) previously (Karthikeyan et al 2004). Also, MYMIV strains were commonly detected in the East of India as previously reported by Malathi and John (2008).…”

“…These results indicated that the tolerance in NM 94 still was effective in the field against local isolates of Mungbean yellow mosaic India virus, genetically most similar to the MYMIV Bengal isolate [HF922628] found in West Bengal and in this study in Jharkhand, and to local isolates of Mungbean yellow mosaic virus genetically most similar to the BVignaŝ trains found in this study and also reported by Karthikeyan et al (2004) in the South of India. The reduced tolerance (susceptibility) of NM 94 in the field in Northern India during the Kharif season may be due to the greater inoculum pressure under these conditions as whitefly populations might build up to very high levels during this time (Varma et al 2011).…”

Gamma rays induced urdbbean [Vigna mungo (L.) Hepper] mutants with YMV resistance, good batter quality and bold seeded type

“…Of these MYMIV and MYMV are most important as these infect large number of legumes in India. MYMIV is more predominant in northern, central and eastern regions of India (Usharani et al 2004) and MYMV in southern region (Karthikeyan et al 2004;Girish and Usha 2005;Haq et al 2011) to which Tamil Nadu state belongs.…”

Screening of Superior Genotypes for Cold Tolerance and MYMV Resistance in Greengram (Vigna radiata)

“…The disease is caused by white fly (Bemicia tabaci) transmitted begomo gemini viruses with bipartite genomes (Varma and Malathi, 2003). Begomoviruses are a group of plant viruses containing single-stranded circular DNA encapsidated in geminate particles (Khattak et al, 2000;Karthikeyan et al, 2004). Greengram plants infected with yellow mosaic disease generally show yellowing or chlorosis of leaves followed by necrosis, shortening of internodes, and severe stunting of plants with no yield or few flowers and deformed pods produced with small, immature and shriveled seeds (Akhtar et al, 2009).…”