Judul: Respons Ketahanan Sumberdaya Genetik Lokal Cabai (Capsicum spp.) terhadap Infeksi Virus Daun Keriting Kuning dan Identifikasi Faktor Inisiasi Translasi 4E (eIF4E)
Abstrak: Chili pepper (Casicum spp.) is one of the most important horticultural crops in Indonesia. The limiting factors to improve the total production and quality in chili ware caused by pepper yellow leaf curl virus, was transmitted by the insect called Bemisia tabaci Genn. Economically, yield loss due to viral infection are very high due to persistent viral attacks. The use of resistant genotypes is one of the most effective methods to control the disease. To obtain resistant varieties, a series of plant breeding activities are required, starting from finding sources of germplasm, selecting parental lines, crossing, developing genotypes, testing genotypes and releasing varieties. Screening for resistance to viral infection was carried out on 14 genotypes of chili collections from the Center for Tropical Horticultural Studies (PKHT). The research activities included testing the resistance response of 14 genotypes of chili plants against pepper yellow leaf curl virus, and identification of translation initiation factor 4E as a candidate gene responsible for recessive resistance. The first activity was aimed to obtain resistant genotype candidates from 14 local genotypes chili pepper collection from PKHT. The artificial inoculation was carried out on 14 genotypes of chili peppers through B. tabaci as a vector which previously acquired on plants infected by yellow leaf curl virus. The study was conducted in a greenhouse using a one-factor randomized complete block design, with genotype as a factor and replicated 3 times. Observation parameters include disease incubation period, scoring the disease symptom, disease incidence and severity values, several quantitative plant characters, heritability in broad sense values and correlations between quantitative characters. The results grouped plants into four categories, resistant, moderately resistant, moderately susceptible and susceptible. Genotypes with susceptible categories, were PKHT-4 and CR-MH, moderately susceptible were PKHT-2, PKHT-3, PKHT-5, CR-SH, moderately resistant were PKHT-1, PKHT-6, PKHT -7, CR-SA, CB-BA, CB-BJ, and CB-CA, and the only resistant category were found in genotype CB-EL. The broad sense heritability values for disease resistance were moderate-high categories, and the correlation quite high. This showed that selection for the disease resistance against virus can be done at the early stage of planting, and the genotypes which show resistant character can be developed as a parental candidates. To see the presence of viral infection in plants, molecular analysis was carried out using degenerate primers Begomovirus SPG1/SPG2. The amplification results produce a band size around 900 bp. This indicates that the plant is positively infected with the disease-causing virus. The second activity was isolation and identification of translation initiation factor 4E (eIF4E) to obtain candidate genes responsible for recessive resistance against Begomovirus infection. The results of amplification with primers AY122F/AY122R were 500 bp, in accordance with the expected size of the primer, which was 529 bp. It showed that the fragment of the DNA was detected and amplified, except for the genotipe number 13 (no band produced), which was CB-EL. It is suspected that the CB-EL genotype has resistance that is controlled by the recessive allele. Lost of function of eIF4E inhibited viral proliferation and the CB-EL genotype was not detected during amplification using S-gene primers. Furthermore, sequencing was
Keyword: B. tabaci, heritability, recessive resistant, selection