<div style="text-align:justify">Background: Vigna mungo (Blackgram) is the major pulse crop cultivated in the Indian sub-continent. It is highly prone to yellow mosaic disease (YMD), which is widespread problem because all cultivated varieties are susceptible to the YMD in Andhra Pradesh state. The presence of two species of begomovirus i.e. Mungbean yellow mosaic virus (MYMV) and Mungbean yellow mosaic India virus (MYMIV) with YMD was reported in Andhra Pradesh. The current study was aimed to develop simple method of viral dimer clone construction and identifying the resistant blackgram genotypes against two species of begomovirus (MYMV and MYMIV) by agroinoculation technique. 
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Methods: In this study, we standardize the rolling circle amplification (RCA) based viral dimer clone construction (MYMV DNA-A, MYMV DNA-B and MYMIV DNA-A) and constructed viral dimer clones were used to transform Agrobacterium tumefaciens EHA105 cells through freeze-thaw technique. Sprouted seed method of agroinoculation screening was conducted. 
 
Result: Total 45 blackgram genotypes were screened by sprouted seed method of agroinoculation with two combinations of viral dimeric constructs (MYMV-TPT-A+MYMV-TPT-B and MYMIV-TPT-A+MYMV-TPT-B). Twenty four genotypes offered resistant against MYMV infection and twenty three genotypes were resistant to MYMIV infection. Total 17 genotypes offered resistance to both species of virus (MYMV andMYMIV) associated with YMD.</div>

Construction of Full-length Dimer Clones of Yellow Mosaic Virus and Screening of Blackgram Germplasm using Agroinoculation

<div>Background: Mung bean Yellow Mosaic Virus (MYMV) is found to be one of the prime viral diseases of mungbean in Tamil Nadu state. Screening for MYMV resistance in field condition always remains a hassle for breeding society. The peculiar MYMV symptoms often failed in the field due to some factors such as environmental changes, whitefly genotypes, host factors etc. With the above perspective, the present study aimed to screen the mung bean derivatives against MYMV through a novel in vitro agroinoculation technique and further substantiation through whitefly transmission. 
 
Methods: Four interspecific derivatives (VGGRU 1, VGGRU 2, VGGRU 3 and VGGRU 4) generated by making crosses between mungbean VRM (Gg) 1 and rice bean (TNAU RED) along with the susceptible check VRM (Gg) 1 were agroinoculated with the MYMV infectious clone VA 239 (KA30 DNA A + KA27 DNA) and are further substantiated through whitefly transmission studies from the artificially reared whiteflies. &nbsp; 
 
Result: The agroinoculation results revealed that among the four interspecific derivatives, VGGRU 1 was found to be completely resistant to MYMV. The substantiation of the obtained result through whitefly transmission also revealed that 24 h Acquisition Access Period (AAP) and 24 h Inoculation Access Period (IAP) with Bemisia tabaci able to cause 65% infectivity in susceptible plant VRM (Gg) 1 and zero infectivity in VGGRU 1 and the results were PCR confirmed for the presence of viral DNA.</div>

Identification and Confirmation of Resistance in Mungbean [Vigna radiata (L.) Wilczek] Derivatives to Mungbean Yellow Mosaic Virus (MYMV)