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French bean seed samples were collected from different parts of Tamil Nadu including both tropical and temperate region including four cultivars viz., Arkakomal, Premier, Rajmash DPU 88-4 and Watex. The variety Watex was found to maximum per cent seed infection of C. lindemuthianum with more discolorations. Among the various techniques adopted for detection, agar plate method was found to be best and yielded maximum per cent seed infection. Direct correlation was obtained between seed discoloration and per cent seed infection. The pathogen was found to be present mostly in seed coat and cotyledon and rarely in embryonic axis. The artificial inoculation of 45-day-old plants resulted in maximum disease incidence, resultant seed infection and minimum seed yield /plant and 100 grain weight.

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A polymerase chain reaction (PCR) assay was used to detect the Indian isolate of banana bunchy top virus at early stages of infection in banana suckers before symptom expression. The viral DNA was detected from a single viruliferous banana aphid (Pentalonia nigronervosa) at 1.0 kb. The six plant species viz., Zingiber officinale, Colocasia esculenta, Catheranthus roseus, Canna indica, Hedychium coronarium and Alphinium sp. upon inoculation with BBTV showed negative results in PCR assay. Using PCR assay the BBTV could be detected in meristem tip cultured banana plants before symptom expression. In field condition the meristem tip cultured banana plants expressed BBTV symptom 45 days after planting.

A cDNA encoding thaumatin-like protein (TLP) from rice was cloned into the binary vector pMON410 under the control of the CaMV 35S promoter for Agrobacterium-mediated transformation of tomato. All putative transformants were tested for the integration and expression of the chimeric gene by polymerase chain reaction (PCR) for hygromycin resistance gene (hph) and enzyme-linked immunosorbent assay (ELISA) for TLP respectively. Constitutive, high-level expression of TLP was observed in transgenic plants. The transgenic lines exhibited increased resistance to Alternaria solani, the early blight pathogen compared to non-transgenic tomato plants.

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