First Report of Tobacco streak virus Infecting Pigeon Pea (Cajanus cajan) in India

Abstract

Kpnl digestion. The fragments were cloned in pUC19 and sequenced. The partial sequences of four isolates were >95% idenfical to each other at the nucleotide (nt) level and thus only one isolate (P-25) was fully sequenced, determined to be 2,572 nt in length, and its sequence deposited in Gen-Bank (KFl 11683). The P-25 sequence showed a genome organization typical of a mastrevirus, with four open reading frames (ORFs), two in virion-sense and two in complementary-sense. The vidon and complementary-sense ORFs were separated by a long intergenic region, containing a predicted hairpin structure with the nonanucleotide sequence (TAATAT TAC) in the loop, and a short intergenic region. An initial comparison to all sequences in the NCBI database using BlastN showed the isolate to have the highest level of sequence identity with isolates of the dicot-infecting mastrevirus Chickpea chlorotic dwarf virus (CpCDV). Subsequent alignments of all available CpCDV isolates using the species demarcation tool (2) showed the isolate P-25 to share between 83.6 and 90.3% idendty to isolates of CpCDV available in databases, with the highest (90.3%) to CpCDV strain A odginafing from Syda (FR687959) (3). Amino acid sequence compadson showed that the predicted proteins encoded by the four ORFs of P-25 (coat protein [CP], movement protein [MP], replication associated protein A [RepA], and RepB) share 91.5, 88.2, 89.1, and 90.8% amino acid sequence identity, respectively, with the homologous proteins of the CpCDV isolate from Syda. Based on the recently revised mastreviruses species and strain demarcation criteria (78 and 94% whole genome nt identity, respectively) proposed by Muhire et al. (2), the results indicate that isolate P-25 represents a newly identified strain (strain F) of CpCDV. The pre.çence of CpCDV in symptomatic pepper plants was further confirmed by Southem blot hybddization technique using digoxygenin (DIG) labeled probe prepared from CpCDV isolate P-25. The genus Mastrevirus consists of geminiviruses with single component genomes that are transmitted by leafhoppers. Mastreviruses have so far only been identified in the Old World and infect either monocotyledonous or dicotyledonous plants (1). To our knowledge, this is the first report of a mastrevirus on the Arabian Peninsula and the first record of pepper as host of CpCDV. Recently, several begomoviruses of diverse geographic origins have been found infecting vegetable crops in Oman. The propensity of geminiviruses to evolve through recombination may lead to evolution of recombinant CpCDV with new host adaptability. Due to extensive agricultural/travel links of Oman with rest of the world, there exists high probability for the spread of this virus.

Molecular characterization of emaraviruses associated with Pigeonpea sterility mosaic disease

“…SMD infected pigeonpea samples from the field may be infected by other viruses as low and rare incidences of other viral infections 67 , 68 have been reported. In addition, Tobacco streak virus (TSV) has been reported affecting pigeonpea plants in the fields 69 .…”

Molecular characterization of a novel cryptic virus infecting pigeonpea plants

“…Pigeonpea [Cajanus cajan (L.) Millspaugh], having originated in India, is one of the major grain legume (pulse) crops in the Indian subcontinent. The crop is known to be susceptible to a few virus and virus-like pathogens, belonging to different genera [1][2][3][4]. While characterizing the dsRNA from the sterility mosaic disease (SMD) [3] affected pigeonpea plants, we noticed that two sets of symptomless controls plants containing four dsRNA molecules while none were noticed in the remaining sets of healthy samples.…”