Optimization of RQRT-pCR protocols to measure beta-1,3-glucanase mRNA levels in infected tissues of rubber tree (Hevea brasiliensis).

RQRT-PCR technique was evaluated for its validity as an alternative to Northern blotting for quantification of plant gene expression in diseased tissues of Hevea. Reliable RT-PCR results could be obtained by co-amplification of housekeeping actin gene as the internal control along with the gene of interest. The product of interest was quantified relative to that of the internal control by measuring net intensity of bands. Expression levels of defense-related beta-1,3-glucanase gene was studied in the pathogen infected tissues of rubber. The beta-1,3-glucanase gene was found to be induced in infected leaf tissues and reached a peak at 48 h after inoculation. The beta-1,3-glucanase gene expression during pathogen infection was determined through Northern blot hybridization also, using 18S RNA as the internal control. RQRT-PCR and Northern hybridization showed almost similar results, thereby validating the use of this technique to study the gene expression in rubber.

Bemnisia tabaci feeding induces pathogenesis-related proteins in cassava (Manihot esculenta Crantz).

Cassava (Manihot esculenta Cranzts) plants fed upon by whitefly Bemisia tabaci showed increased levels of pathogenesis-related (PR) proteins, such as beta-1, 3-glucanase, peroxidase and chitinase activities, as compared to uninfested plants. The enzymes increased in specific activities from 2 to 7 fold and protein content in leaf extracts decreased in whitefly-infested plants, compared to uninfested plants. Among the three PR proteins, B. tabaci feeding induced significantly higher beta-1, 3-glucanase activities, when compared with other two PR proteins. Study also discussed the possible application of PR proteins in whitefly control program.