An efficient genotype independent method for in vitro regeneration and genetic transformation of Brassica spp. viz. Brassica juncea and Brassica napus have been developed for the local varieties using cotyledonary leaf with petioles and hypocotyls as explants. Explants obtained from 6-day old aseptically grown seedlings were inoculated and co-cultivated with Agrobacterium tumefaciens strain EHA105 harbouring a binary vector with PDH45 gene under the regulatory control of 35s promoter and terminator sequences, permitting transformed shoots to be selected on hygromycin containing medium. Well rooted transformed plants were transferred to pots containing soil and after acclimatization the plants were maintained under controlled environmental condition. A total of 9 transformed plants were obtained from BARI Sarisha-8 variety, presumably indicating this protocol is more amenable to genotype independent genetic transformation. Integration and expression of the introduced transgene (PDH45 and hptII) were analysed by polymerase chain reaction (PCR). Factors influencing transformation efficiency include explant age, optical density of Agrobacterium culture for infection, duration of infection and co-cultivation with Agrobacterium were also assessed. Genetic transformation method developed in this study certainly could be utilized for introducing abiotic stress resistance in the local cultivars of oilseed Brassica. Dhaka Univ. J. Biol. Sci. 30(3 CSI): 345-358, 2022 (June)

Jute (Corchorus sp.), is a versatile, naturally occurring, biodegradable material that holds the promising possibility of diminishing the extensive use of plastic bags. One of the major components of the cell wall, lignin plays both positive and negative roles in fiber fineness and quality. Although it gives mechanical strength to plants, an excess amount of it is responsible for the diminution of fiber quality. Among various gene families involved in the lignin biosynthesis, Caffeoyl-CoA 3-O-methyltransferase (CCoAOMT) is the most significant and has remained mostly unexplored. In this study, an extensive in-silico characterization of the CCoAOMT gene family was carried out in two jute species (C. capsularis L. and C. olitoroius L.) by analyzing their structural, functional, molecular and evolutionary characteristics. A total of 6 CCoAOMT gene members were identified in each of the two species using published reference genomes. These two jute species showed high syntenic conservation and the identified CCoAOMT genes formed four clusters in the phylogenetic tree. Histochemical assay of lignin in both jute species could shed light on the deposition pattern in stems and how it changes in response to abiotic stresses. Furthermore, expression profiling using qPCR showed considerable alteration of CCoAOMT transcripts under various abiotic stresses and hormonal treatment. This study will lay a base for further analysis and exploration of target candidates for overexpression of gene silencing using modern biotechnological techniques to enhance the quality of this economically important fiber crop.

The aim of the present investigation was to develop an efficient and reproducible in vitro regeneration protocol for Brassica campestris L. var. Tori-7. Brassica is one of the most popular and major oil yielding crop plants around the world including Bangladesh. For in vitro regeneration of this crop plant, MS medium supplemented with various concentrations of 6-benzylaminopurine (BAP) and naphthalene acetic acid (NAA) were used. The highest frequency of callus and shoot regeneration was obtained on MS medium supplemented with 3.0 mg/l BAP and 0.2 mg/l NAA from both cotyledonary leaf with petiole and hypocotyl explants. Elongation of shoots was also optimized on the same media composition. For inducing roots from the excised in vitro derived shoots, half strength of MS medium supplemented with 0.3 mg/l indole-3-butyric acid (IBA) was found to be more effective than other hormonal supplements applied. Following the development of effective roots, in vitro raised plantlets were successfully transplanted into soil where they produced flowers and fertile seeds. The plants of R1 generation was successfully established in natural environment. In vitro regeneration protocol of Brassica campestris var. Tori-7 established in this study could be used for future plant genetic transformation experiments. Plant Tissue Cult. & Biotech. 32(2): 237-246, 2022 (December)