Response of Several Chili Accessions and Molecular Markers to Yellow Leaf Curl Disease

Abstract

Penyakit daun keriting kuning merupakan penyakit penting tanaman cabai dan menjadi kendala utama dalam produksi cabai. Penyakit ini disebabkan oleh Pepper yellow leaf curl virus (PYLCV) dan ditularkan oleh serangga vektor kutukebul Bemisia tabaci (Hemiptera: Aleyrodidae). Penggunaan varietas tahan direkomendasikan sebagai salah satu cara pengendalian penyakit, tetapi belum tersedia varietas cabai tahan PYLCV secara komersial. Penelitian ini dilakukan untuk mengevaluasi ketahanan 10 aksesi cabai koleksi Balai Besar Penelitian Bioteknologi dan Sumberdaya Genetik Pertanian (BBBiogen) dan mengidentifikasi marka molekuler yang berhubungan dengan sifat ketahanan cabai terhadap PYLCV. Tanaman cabai uji berumur 30 hari setelah tanam diinokulasi PYLCV menggunakan kutukebul dengan periode makan akuisisi dan inokulasi masing-masing 48 jam, dengan 10 ekor kutukebul per tanaman. Respons tanaman diamati berdasarkan gejala, insidensi dan keparahan penyakit. Konfirmasi infeksi PYLCV pada tanaman uji dilakukan dengan metode deteksi polymerase chain reaction (PCR) menggunakan primer universal Begomovirus. Gejala penyakit pada tanaman cabai uji meliputi daun menguning, tulang daun menebal serta memucat, serta tanaman kerdil. Insidensi dan keparahan penyakit pada tanaman cabai uji berturut-turut berkisar 0-36% dan 0-28%; sedangkan pada tanaman kontrol rentan PYLCV, yaitu varietas Bara berturut-turut 88% dan 61%. Delapan dari 10 galur cabai uji menunjukkan respons tahan terhadap PYLCV. Pola polimorfisme pada galur cabai uji diperoleh dengan marka CaBR61 dan CaBR98, walaupun dua marka tersebut tidak dapat digunakan sebagai penanda respons ketahanan terhadap PYLCV.

Yellow leaf curl disease is an important disease of chili plants and a major obstacle to chili production. This disease is caused by Pepper yellow leaf curl virus (PYLCV) and is transmitted by the whitefly vector Bemisia tabaci (Hemiptera: Aleyrodidae). The use of resistant varieties is recommended for controlling this disease, but there are no commercially resistant PYLCV varieties available. This study was conducted to evaluate the resistance of 10 chili accessions from the collection of Balai Besar Penelitian Bioteknologi dan Sumberdaya Genetik Pertanian (BBBiogen) and to identify molecular markers associated with chili resistance to PYLCV. Thirty days-old chili plants were inoculated with PYLCV using whitefly with acquisition and inoculation feeding periods of 48 hours each, and 10 whiteflies per plant. Plant response was observed based on symptoms, incidence, and severity of the disease. Confirmation of PYLCV infection in the test plants was carried out by polymerase chain reaction (PCR) detection method using Begomovirus universal primer. Symptoms of the disease in the tested chili plants include leaf yellowing, thickening and blanching of leaf veins, and stunting of the plants. Incidence and severity of the disease in the tested chili plants ranged from 0-36% and 0-28%, respectively; whereas in control plants susceptible to PYLCV, i.e., var. Bara was 88% and 61%, respectively. Eight of the 10 tested chili accessions showed resistant response to PYLCV. Polymorphism patterns in chili accessions were obtained with CaBR61 and CaBR98 markers, although these two markers cannot be used as markers for resistance response to PYLCV.