A high-throughput regeneration protocol for recalcitrant tropical Indian maize (Zea mays L) inbreds

Immature embryos from five select recalcitrant maize (Zea mays L) inbreds used as explants were evaluated for their ability to form callus, somatic embryos and subsequent regeneration into plants. The embryos were placed on N6 basal media with varying levels of 2,4-D (0.5, 1.0, 1.5, 2.0, and 2.5 mg l-1) and were regenerated on MS me¬dium supplemented with BAP (2 - 10 mg l-1), 2,4-D (0.25 mg l-1) and silver nitrate (0.85 mg l-1). Explants cultured on N6 medium supplemented with 2,4-D (2.0 mg l-1) were associated with the highest frequency of embryogenic calli and that of UMI 29 were highly embryogenic (78.67%). When synergism between dicamba and 2,4-D on Type II callus production in UMI 29 was sought to be investigated using 2,4-D (1 or 2 mg l-1) individually and in combina¬tion with dicamba (3.7 mg l-1) production of Type II callus with the greatest frequency of 83.33% was observed on N6 medium containing 3.7 mg l-1 dicamba + 1 mg l-1 2,4-D. The greatest percentage of shoot induction (82.67%) was observed on MS medium supplemented with BAP (10 mg l-1). Among the five genotypes tested, UMI 29 was associated with the highest percentage of callus initiation, shoot induction and mean number of developed shoots. The protocol described in this study can reliably be used to transform tropical maize inbreds as a routine

Genetic engineering of cotton with a novel cry2AX1 gene to impart insect resistance against Helicoverpa armigera

Embryogenic calli of cotton (Coker310) were cocultivated with the Agrobacterium tumefaciens strain LBA4404 harbouring the codon-optimised, chimeric cry2AX1 gene consisting of sequences from cry2Aa and cry2Ac genes isolated from Indian strains of Bacillus thuringiensis. Forty-eight putative transgenic plants were regenerated, and PCR analysis of these plants revealed the presence of the cry2AX1 gene in 40 plants. Southern blot hybridisation analysis of selected transgenic plants confirmed stable T-DNA integration in the genome of transformed plants. The level of Cry2AX1 protein expression in PCR positive plants ranged from 4.9 to 187.5 ng g-1 of fresh tissue. A transgenic cotton event, TP31, expressing the cry2AX1 gene showed insecticidal activity of 56.66 per cent mortality against Helicoverpa armigera in detached leaf disc bioassay. These results indicate that the chimeric cry2AX1 gene expressed in transgenic cotton has insecticidal activity against H. armigera

Increase in root branching enhanced ferric-chelate reductase activity under iron stress in potato (Solanum tuberosum)

Not AvailableIn response to Fe-deficiency, various dicots increase their root branching to improve ferric-chelate reductase activity. It still remains unclear, whether the response caused by Fe-deficiency ultimately improves the plant's ability to withstand Fe-deficiency. In this experiment conducted at ICAR-Central Potato Research Institute, Regional Station, Shillong during 2020, we demonstrated a substantial increase in the growth of the lateral root of potato genotype (CP 3443), when grown in the iron-stress, in relation to control plants, and the total lateral root number is well linked to ferric-chelate reductase (FCR) activity. These findings showed that FCR is involved in root Fe uptake in potato (Solanum tuberosum L.) and they suggest a role in Fe distribution throughout the plant. In view of these findings, the Fe-deficiency induced increases in the lateral roots suggested that these play a significant role in Fe-deficiency tolerance in potato, which can serve as useful trait for the identification of chlorosis tolerance and/or nutrient-deficiency stress

Additional file 1: of Over-expression of a NAC 67 transcription factor from finger millet (Eleusine coracana L.) confers tolerance against salinity and drought stress in rice

Table showing the list of primers used in the study. (PDF 42 kb