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Indonesia is one of the world's largest fresh pepper (Capsicum spp.) fruit-producing countries, and hot peppers are essential spices in Indonesian cuisine. During the last two decades, begomovirus, which is transmitted by the whitefly, Bemisia tabaci (Gennadius), and causes pepper yellow leaf curl disease, began to cause a huge economic loss by damaging pepper plants in Indonesia. In the present study, a highly efficient inoculation method was established for Pepper yellow leaf curl Indonesia virus (

Tomato yellow leaf curl disease caused by begomoviruses is a serious threat to tomato (Solanum lycopersicum L.) production. If begomoviruses, transmitted by whitefly (Bemisia tabaci), infect tomato plants during early growth, production can be almost entirely lost. Tomato yellow leaf curl Kanchanaburi virus (TYLCKaV), a bipartite Begomovirus, is emerging as an important threat to solanaceous crop production in Southeast Asia. The lack of mechanical transmission of some begomoviruses is a major experimental constraint. In this study, an agroinoculation method using TYLCKaV in tomato plants was established. Partial tandem repeats of TYLCKaV DNA A and DNA B were constructed and cloned to a binary pGreenII vector, and their infectivity was tested. Co-inoculation of TYLCKaV DNA A and DNA B to Nicotiana benthamiana L. produced typical begomoviral symptoms, and both of the viral DNA components accumulated in the upper uninoculated leaves, suggesting systemic infection of TYLCKaV. Two agroinoculation methods were conducted on tomatoes. First, excised sections of tomato shoots were agroinoculated with a soaking procedure. Although two Agrobacterium tumefaciens strains were tested, approximately 40% of inoculated plants only showed viral symptoms for EHA105. Second, agrobacterium from a cultured petri dish was directly inoculated with a colony inoculation procedure. When EHA105 was used, approximately 92% of inoculated plants showed viral symptoms. Sequencing the recovered viral DNA from the upper uninoculated leaf clarified that TYLCKaV had successfully infected the tomato plants. The colony inoculation procedure is labor-saving, and viral symptoms develop in susceptible tomato plants within approximately a month from sowing the seeds. This method could contribute to simple and speedy evaluation of TYLCKaV resistance of tomato plants.

Pepper yellow leaf curl disease (PepYLCD) caused by begomoviruses is one of the most devastating diseases affecting pepper (Capsicum spp.) production worldwide. In our previous study, a loss-of-function allele, pepy-1, encoding messenger RNA surveillance factor Pelota was identified as a begomovirus resistance gene from a C. annuum cultivar BaPep-5. In this study, to investigate the effectiveness of pepy-1 conferred resistance against begomovirus in the field, we conducted a three-year evaluation under natural field conditions in Indonesia. The lowest PepYLCD incidence and significantly higher fruit productivity were observed in BaPep-5 when compared to six other commonly cultivated pepper cultivars. The subsequent comparison between BaPep-5 and the susceptible BaPep-4 showed that pepy-1 slowed down the disease onset and progression, resulting in a higher fruit productivity trait in the field. Multiple comparison analyses using an F 2 population obtained by crossing BaPep-5 with BaPep-4 showed that the pepy-1 homozygous individuals had significantly higher fruit productivity, twice than those of the Pepy-1 homozygous or heterozygous individuals. In conclusion, the introgression of pepy-1 is effective to reduce the economic loss of pepper fruit production under natural field infection of begomoviruses.

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