Induced Expression of Cytochrome P450 CYP305 B1V1 Gene in Different Tissues of Wild Mulberry Silkworm(Bombyx mandarina)

[ Objective] The aim of this study was to investigate effects of various inducers on the expression of cytochrome P450 CYP305 B1 V1 Gene in different tissues of wild mulberry silkworm. [ Method] Referring to the mRNA sequence of CYP305 B1 V1 Gene published in GenBank for wild mulberry silkworm, one pair of primers was designed, and the expression of cytochrome P450 CYP305 B1 V1 Gene in different tissues of wild mulberry silkworm treated by NaF, rutin, cypermethrin and ecdysone was also analyzed by the semi - quantitative RT - PCR. Furthermore, homology comparison and phylogenetic analysis for amino acid sequences of this gene were studied. [ Result] Rutin, cypermethrin and NaF had effects on the expression of P450 CYP305 B1 V1 Gene in different tissues of wild mulberry silkworm, while ecdysone had no significant effect. Homology comparison for amino acids indicated that the amino acid sequence of this gene was the most similar to that of CYP305 B1 gene in Bombyx mori with 100% amino acid identity, and highly similar to those of Tribolium casmneum CYP305A1, Apis mellifera CYP305A1, Drosophi- la melanogaster CYP305A1, Anopheles gambiae CYP305A2and Culex pipiens quinquefasciatus CYP2LI. [ Conclusion] CYP305 B1 V1 Gene of wild mulberry silkworm is likely to mainly take part in the metabolism of exogenous compounds, which is of great significance for revealing the function of cytochrome P450 and the metabolic mechanism of different drugs.

<i>In Vitro</i>Plant Regeneration of <i>Morus indica</i>L. cv. V1 Using Leaf Explant

Adventitious bud induction and plantlet regeneration were studied in a popular mulberry variety, V1 using leaf as an explant. Fully expanded leaf explants were cultured on Murashige and Skoog’s (MS) medium supplemented with thidiazuron (TDZ) (0.5-4.0 mg/l), 6-benzylaminopurine (BAP) (0.5-2.0 mg/l), indole acetic acid (IAA) (2.0 mg/l), gibberlic acid (GA3) (1.0-2.0 mg/l) silver nitrate (AgNO3) (2.0 mg/l) and different carbon sources such as sucrose, fructose and glucose (10%-30%) either individually or in combination to induce adventitious buds and regeneration. The highest percentage (63%) of adventitious bud formation and regeneration (68%) was achieved in the medium containing MS with TDZ (1.0 mg/l), IAA (2.0 mg/l) and AgNO3 (2.0 mg/l). For subsequent regeneration and shoot elongation the MS medium having BAP (1.0 mg/l), GA3 (2.0 mg/l) and AgNO3 (2.0 mg/l) was found to be suitable. Amongst the carbon sources tested, the most suitable carbon source was found to be sucrose (3%) followed by fructose (2%) for adventitious bud formation. Excised in vitro shoots were rooted (60%-80%) in half strength MS medium supplemented with indole-3-butyric acid (1.0 mg/l). The well rooted plantlets were hardened in soil + sand + farm yard manure (FYM) mixture with a success rate of 70%-90%. Since in vitro regeneration is highly genotype-dependent in mulberry, the standardized protocol can be effectively used for further improvement of this leading genotype using biotechnological approaches.