Rina Sri Kasiamdari

Identification of binucleate Rhizoctonia as a contaminant in pot cultures of arbuscular mycorrhizal fungi and development of a PCR-based method of detection

Binucleate Rhizoctonia (BNR) was isolated (isolate CFM1) from cabbage grown in soil from pot cultures of the arbuscular mycorrhizal (AM) fungus, Glomus mosseae grown on subterranean clover, and was identified as AG-Bo by means of morphological and molecular characteristics. A PCR-based assay was developed to detect BNR in roots and soils of pot cultures of AM fungi. Two oligonucleotide primers (CF1f and CF2r) were designed from the ITS region of the rDNA sequence of BNR AG-Bo isolate CFM1. These allowed amplification of a specific fragment (438 bp). Specificity of the primers was tested against several isolates of various anastomosis groups (AGs) of BNR, other related and unrelated fungal species, and roots not infected or infected with fungi. The primers amplified DNA of isolates of both BNR AG-Bo and AG-A, and were used to detect them in roots in the presence or absence of AM fungi. Nested PCR amplification using CF1f and CF2r primers has advantages over microscopic methods for detection of BNR AG-Bo or AG-A on infected roots and soils of AM pot cultures and provides a powerful tool for detection of contamination of these pot cultures.

Resistance Response of Chilli (Capsicum annuum L.) F1 to Fusarium oxysporum Involves Expression of the CaChi2 Gene

Cross-breeding is a method of producing progeny with better resistance to pathogens. Resistance to pathogens usually involves pathogenesis-related (PR) proteins. Class II chitinase is an example of a defensive PR protein in plants. The class II chitinase in chilli is coded by the CaChi2 gene. In this study, we crossed susceptible with resistant chilli cultivars, analysed the F1 resistance response against pathogenic F. oxysporum, and analysed the level of CaChi2 gene expression in the F1. Data were collected using disease severity index (DSI) determination and gene expression analysis by qRT-PCR (quantitative Reverse Transcriptase Polymerase Chain Reaction). Results showed that the DSI of F1 was not significantly different from the resistant ancestor. The relative CaChi2 expression level of F1 was higher than the susceptible ancestor but not significantly different from the resistant ancestor. We concluded that the F1 can be categorised as resistant to F. oxysporum, and the CaChi2 gene is involved in the molecular defense response.

Systemic inducing resistance against late blight by applying antagonist Trichoderma Viride

Biological control by Phytophthora infestans (Mont.) de Bary, a pathogen causing late blight disease on potatoes, has attracted scholars as an environmentally alternative preference to chemical pesticide. Some species of Trichoderma spp. has proven to be capable of triggering resistance mechanism of plant against fungal pathogens. The aim of this research was to analyze the effect of Trichoderma viride SP1 suspension to induced systemic resistance on potato plant as showing glucanase activity and total phenol content. The method used was Completely Randomized Design with six treatments and seven times repeated. Variables observed were total phenol content and total crop. The result showed that glucanase activity and total phenol content in plants treated with Trichoderma viride and fungicide (1587 μg/g and 1934 μg/g) significantly increased. In addition, T. viride enhanced induced systemic resistance on potato plant and increased potato yield.

Detection of polymorphisms on strawberry (Fragaria spp.) based on cleavage amplified polymorphic sequence

Strawberries (Fragaria spp.) represent a fruit of high economic value. However, its cultivation in Indonesia has not been optimal. Along with the development of technology, plant researchers and breeders have been developing new cultivars to improve the quality of strawberry plants. Morphological selection of superior quality cultivars was found less effective, leading to the development of molecular research. One method to evaluate the result of breeding strawberry plants is to use the Cleavage Amplified Polymorphic Sequence (CAPS) markers, which can be used for the identification of octoploid strawberry cultivars. The purpose of the present study was to investigate the polymorphic banding pattern of strawberry cultivars grown in Indonesia, to determine CAPS marker capabilities for detection of polymorphisms, and to determine the degree of similarity of strawberry cultivars in Indonesia based on the CAPS markers. The samples were 12 strawberry cultivars from the Citrus and Subtropical Fruit Research Inst...

The occurrence and identification of powdery mildew on melon in Java, Indonesia

Powdery mildew is a serious disease and causes considerable decline in production and fruit quality of melon (Cucumis melo L.) grown in Java, Indonesia. The fungal species that cause powdery mildew in Indonesia have never been reported. Therefore, the lack of knowledge about the biology of these fungi will inhibit in the handling of the eradication of powdery mildew further. A survey was conducted in 58 locations of melon cultivation in Central Java, East Java and West Java to study the occurrence of powdery mildew in Java. Powdery mildew species involved in the disease development were identified morphologically based on the anamorph characters such as the mycelium/hyphae, germ tube, appressoria, conidia and fibrosin bodies. In order to confirm the identification, the complete ITS (internal transcribed spacer) region of rDNA of powdery mildew species was amplified using ITS 1 and ITS 4 primers, sequenced directly and compared with sequences from the GenBank. Twelve isolates of powdery mildew species were...