Archivio Journal of Plant Pathology

Abstract:

Maca (Lepidium meyenii), also known as Peruvian gin- seng, is a herbaceous biennial plant of the crucifer family native to the high Andes. During a survey in November 2014, maca plants showing dwarfing and thickening of the main leaf veins, were observed in Huize county of Yunnan province (Southwest China). The incidence of symptomatic plants was approximately 50% and aphids were observed in the fields. Two symptomatic plants were collected and tested for the presence of viruses. Flexuous filamentous particles 700-750 nm in length were observed with the electron microscope in leaf dips suggesting the presence of an aphid-transmitted potyvirus. To investigate this hy- pothesis, total RNA was extracted using TRIzol reagent (Invitrogen, USA) and tested by RT-PCR (Chen et al., 2001). The first strand cDNA synthesis was conducted using Po- tyviridae universal primer M4-T (5’-GTTTTCCCAGT- CACGACTTTTTTTTTTTTTT-3’), and PCR was done with primers M4 (5’-GTTTTCCCAGTCACGAC-3’) and S (5’-GG(A/G/C/T)AA(C/T)AA(C/T)AG(C/T)GG(A/G/ C/T)CA(A/G)CC-3’). An amplicon of approximately 1.7 kb was obtained from both diseased samples, indicating the presence of a potyvirus. The RT-PCR products were cloned into pGEM-T Easy vector (Promega, USA) and sequenced. Sequences of 1,689 bp of two isolates were identical and shared 100% nucleotide sequence identity with an isolate of Turnip mosaic virus (TuMV) from China (CHN12) (Gen- Bank accession No. AY090660). The sequence of this maca isolate (TuMV-maca) was deposited in GenBank as accession number KP637171. To our knowledge, this is the first report of TuMV infecting maca.