Karakteristik morfologi dan sebaran tipe kawin Phytophthora capsici asal lada di Pulau Jawa

Abstract

ABSTRAKLada (Piper nigrum) merupakan tanaman rempah unggulan Indonesia, namun beberapa tahun terakhir ini mengalami penurunan produksi akibat gangguan penyakit busuk pangkal batang yang disebabkan oleh cendawan Phytophthora capsici. Cendawan ini mempunyai dua tipe kawin, yaitu A1 dan A2 yang berperan penting dalam reproduksi seksual dan pembentukan oospora. Perpindahan bibit lada dari satu daerah ke daerah lain sangat berpotensi mengubah peta sebar tipe kawin patogen tersebut. Tujuan penelitian ini ialah menentukan karakteristik morfologi P. capsici asal lada dan mengetahui sebaran tipe kawin P. capsici di Pulau Jawa. Karakteristik morfologi isolat P. capsici ditandai oleh variasi ukuran dan bentuk sporangium serta tipe koloni. Ukuran panjang (p) dan lebar (l) sporangium berkisar antara 15.1-76.2 µm dan 9.8-44.8 µm, sedangkan rasio p/l ialah 1.12-2.27. Pengujian tipe kawin menunjukkan bahwa tipe kawin A2 lebih dominan ditemukan dibandingkan dengan tipe kawin A1. Penelitian ini menemukan dua tipe kawin yang berbeda dalam area yang sama, yaitu di Kabupaten Pacitan (Jawa Timur) dan Sleman (Daerah Istimewa Yogyakarta). Berdasarkan temuan penelitian ini disarankan strategi pengawasan yang lebih ketat terhadap distribusi bibit lada dari satu daerah ke daerah lain, khususnya untuk daerah yang belum ditemukan tipe kawin tertentu sehingga kemunculan genotipe baru dari hasil perkawinan kedua tipe kawin yang dikhawatirkan lebih virulen dapat dicegah.Kata kunci: oospora, penyakit busuk pangkal batang, reproduksi seksual, sporangium, tanaman rempah ABSTRACT Pepper (Piper nigrum) is one of the most important spice crops in Indonesia. Recently its production declining due to infection of foot rot disease caused by Phytophthora capsici. This pathogen has two different mating types, namely A1 and A2, in which the presence of opposite two mating types is important for sexual reproduction and formation of oospores. The movement of pepper seedling from one area to another is highly facilitated alteration of mating type distribution map of P. capsici. The objectives of this research were to determine the morphological characteristics and the spread of mating types of P. capsici in Java. Morphology characters of P. capsici isolates were indicated by variation in sporangial size and shape, as well as types of colony appearance. The length (l) and width (w) of sporangium were in the range of 15.1-76.2 µm and 9.8-44.8 µm, respectively; while the l/w ratio was 1.12-2.27. Mating type assay showed that A2 type was more dominantly found than A1 type. This study found two different mating types present in the same area, i.e. Regency of Pacitan (East Java) and Regency of Sleman (Special Region of Yogyakarta). The findings of this research suggested that it is J Fitopatol Indones Rohmah et al. 167required more strict control strategy on the mobilization of black pepper seedling particularly in the area where the certain mating type is not found yet so that the emergence of new more virulent genotype of pathogen can be prevented.

Comparison of growth, viability, sporulation, and virulence of Phytophthora capsici isolated from black pepper (Piper nigrum L.) on various media.

“…Further, P. capsici is able to form chlamydospores as a survival phase and will reform zoosporangia when environmental conditions, such as temperature, light, and availability of nutrients are supportive. [1] explained that the ability of P. capsici to survive during the shelf life would form chlamydospores as survival structures that could survive the lack of nutrition and aeration during the storage period of 40 days. Chlamydospores will form a sporangium again if the availability of nutrients is abundant and environmental conditions support the development of P. capsici hyphae The results of observing the morphological form of P. capsici on various types of media showed that the morphological characteristics of hyphae and colonies before and after 40 days of storage did not change.…”

“…In contrast to fungi in general, P. capsici as a soil-borne pathogen can grow optimally in watersaturated soil conditions, is sensitive to nutrients and the growing media environment, and is easily carried through water, plant residues, and soil. This fungus can also form oospores or chlamydospores as resting structures that is able to survive for decades in the soil, even in extreme environmental conditions [1].…”

“…P. capsici is a soil-borne pathogen that can survive effectively in water-saturated soil conditions, is sensitive to nutrients and the growing media 1297 (2024) 012027 IOP Publishing doi:10.1088/1755-1315/1297/1/012027 2 environment, and is easily spread by water, plant waste, and soil, in opposite to fungi in general. These fungi can also produce oospores or chlamydospores, which are resting structures that can survive in the soil for decades, even in harsh environments [1] The growing media for P. capsici isolates that are often used in laboratories are potato dextrose agar (PDA), corn meal agar (CMA), and vegetable-8 (V8) media with the addition of the antibiotic ampicillin which functions to inhibit bacterial growth [2] However, the effectiveness of media storage in maintaining colony mycelium growth, pathogenicity, and virulence of P. capsici decreased during storage. This causes P. capsici isolate subcultures to be difficult to purify again on PDA, CMA, and V8 media, causing P. capsici isolates cannot be used in the long term [3].…”

Phytophthora capsici on Capsicum Plants: A Destructive Pathogen in Chili and Pepper Crops

“…Under laboratory conditions, the phytopathogen can grow in culture media based on V8 juice [17,18], carrot, tomato, and water agar. Although the growth pattern of the oomycete can be different between isolates, the shape of the colonies is generally rounded and whitish [19], standing out those with a slightly stellate pattern (Figure 1A). The phytopathogen characteristics are: elongated, coenocytic hyphae (Figure 1B); stretched cells with several nuclei [20], measuring between 3 and 8 μm wide [21]; oospores with a diameter between 25.6 and 52.4 μm (Figure 1B) [22].…”

“…The phytopathogen characteristics are: elongated, coenocytic hyphae (Figure 1B); stretched cells with several nuclei [20], measuring between 3 and 8 μm wide [21]; oospores with a diameter between 25.6 and 52.4 μm (Figure 1B) [22]. Its sporangia (Figure 1C) are abundant and formed individually or branched, flaccid or closely spaced [21], mainly spherical (globose, ellipsoid and ovoid), pear-shaped (obpiriform and obturbinate), lemon (limoniform), and/or in some cases irregular (distorted) [19], measuring between 32.1 and 51.3 μm long and 23.3-37.1 μm wide [20]. The main pedicel has a length of 38.3 to 84.4 μm [22].…”