ABSTRACT
The present investigation aimed to look at the effects of biotic and abiotic elicitors during Soybean seed development and cell suspension culture in isoflavones accumulation. The expression levels of four major genes viz., CHS7, CHS8, IFS2, and IFS1 involved on isoflavones biosynthesis during seed developmental stages from R5L-R7 was seen in both MAUS-2 and JS-335 Soybean varieties. The R7 stage showed 1.24-fold upregulation of IFS1transcript level and considered as the control for Soybean seed development. Both varieties during R6-R8 stages responded differently to the foliar application of 10 µM SA, 10 µM MJ and 0.1% Aspergillus niger. The IFS2 transcripts were upregulated by SA at the R7 stage with 5.21- and 4.68-fold in JS-335 and MAUS-2, respectively. IFS1 expression was significantly increased by A. niger treatment at R7 stage with 3.98- and 3.21-fold in MAUS-2 and JS-335, respectively. The expression of CHS7 and CHS8 by 10 µM SA at R7 level revealed maximum up-regulation of 0.51- and 1.01-fold in MAUS-2; 0.37- and 0.82-fold in JS-335, respectively. In the soybean callus suspension culture, biosynthetic genes were used to validate the effects of elicitor on isoflavones. Both biotic and abiotic treatments contribute to the upregulation of IFS1 and IFS2 expression, that in turn, leads to the accumulation of isoflavone in seed development as well as in suspension cultures. These data further suggested that the IFS2 is the key gene responsible for the isoflavone accumulation during elicitor treatment.
ABSTRACT
Development of a reproducible, versatile and efficient in vitro plant regeneration system is highly warranted for Indian soybean varieties for their mass multiplication in view of their commercial significance. Accordingly a protocol for direct shoot organogenesis in soybean variety JS 335 has been developed. Using cotyledonary node explants significant organogenic responses, mean shoot number and shoot length were observed when these were incubated on MS medium supplemented with 0.89 microM Benzyladenine (BA) and 5 microg/L triacontanol (TRIA) where in 9.3 +/- 0.5 shoots were obtained. TRIA at 5 microg/L able to produce 6.8 +/- 0.5 shoot buds in presence of 0.98 microM IBA and 0.89 microM BA. Highest mean shoot buds (14.0 +/- 0.5 and 9.0 +/- 0.5) and mean shoot length (4.6 +/- 0.3 and 10.0 +/- 0.7) were obtained when cotyledonary node and shoot tip explants were cultured on MS medium containing 0.14 microM gibberellic acid (GA3), 0.89 microM BA and 5 microg/L TRIA. Moreover, TRIA supported highest mean root number (6.3 +/- 0.5) and root length (21.5 +/- 0.57 cm). Field survival of in vitro derived plants of TRIA treatment was 70% and the overall growth and seed yield was also significantly better than control plants. This protocol may be used for improving the in vitro regeneration of soybean variety JS 335 for transformation studies.
