Identification and expression of genes associated with shoot regeneration from leaf disc explants of mustard (Brassica juncea) in vitro

Abstract

The identification of genes associated with shoot regeneration from cultured tissues is the first step towards a better understanding of the molecular basis of this process, which is not well understood. In this study, we report the isolation of 87 cDNAs, with 56 homologous to known genes or expressed sequence tags, using mRNA differential display. These cDNAs expressed differentially in tissues grown on shoot induction medium (SIM) in the presence of 10 μM AgNO 3 and control medium (CM) without AgNO 3. After categorizing the cDNAs by putative function, a relatively large fraction (30%) of the cDNA population was found to be associated with ethylene and/or stress-induced responses. Expression of selected cDNAs (A44A, N9B, N15B, N16A, N58C and N92A) in tissues showed a temporal variation of transcript accumulation during 12 days of culture, with transcripts most abundant after 6 and 9 days. Expression of these cDNAs, except N9B, was upregulated by exogenous application of H 2O 2. Both tissues grown on SIM and CM showed similar pattern of H 2O 2 production, which reached a maximum after 6 days, but the level of H 2O 2 in the former and in tissue grown in the presence of ethylene synthesis inhibitor aminoethoxyvinylglycine was generally higher. © 2004 Elsevier Ireland Ltd. All rights reserved.