Agrobacterium-mediated Transformation of Tomato Plants Expressing Defensin Gene

Biomimetic Strategies for Developing Abiotic Stress-Tolerant Tomato Cultivars: An Overview

The tomato is one of the most important vegetables in the world. The demand for tomatoes is high in virtually any country, owing to their gastronomic versatility and nutritional and aromatic value. Drought, salinity, and inadequate temperature can be major factors in diminishing yield, affecting physiological and biochemical processes and altering various metabolic pathways, from the aggregation of low molecular-weight substances to the transcription of specific genes. Various biotechnological tools can be used to alter the tomato genes so that this species can more rapidly or better adapt to abiotic stress. These approaches range from the introgression of genes coding for specific enzymes for mitigating a prevailing stress to genetic modifications that alter specific metabolic pathways to help tomato perceive environmental cues and/or withstand adverse conditions. In recent years, environmental and social concerns and the high complexity of the plant response may increase the attention of applied plant biotechnology toward biomimetic strategies, generally defined as all the approaches that seek to develop more sustainable and acceptable strategies by imitating nature's time-tested solutions. In this review, we provide an overview of some of the genetic sequences and molecules that were the objects of biotechnological intervention in tomato as examples of approaches to achieve tolerance to abiotic factors, improving existing nature-based mechanisms and solutions (biomimetic biotechnological approaches (BBA)). Finally, we discuss implications and perspectives within the GMO debate, proposing that crops modified with BBA should receive less stringent regulation.

Plant defensins: types, mechanism of action and prospects of genetic engineering for enhanced disease resistance in plants

Natural antimicrobial peptides have been shown as one of the important tools to combat certain pathogens and play important role as a part of innate immune system in plants and, also adaptive immunity in animals. Defensin is one of the antimicrobial peptides with a diverse nature of mechanism against different pathogens like viruses, bacteria and fungi. They have a broad function in humans, vertebrates, invertebrates, insects, and plants. Plant defensins primarily interact with membrane lipids for their biological activity. Several antimicrobial peptides (AMPs) have been overexpressed in plants for enhanced disease protection. The plants defensin peptides have been efficiently employed as an effective strategy for control of diseases in plants. They can be successfully integrated in plants genome along with some other peptide genes in order to produce transgenic crops for enhanced disease resistance. This review summarizes plant defensins, their expression in plants and enhanced disease resistance potential against phytopathogens.

In vitro regeneration of eight cultivars of Brassica oleracea var. capitata

Eight cultivars of Brassica oleracea var. capitata and two types of explant (hypocotyl and cotyledon) were tested for their potential to regenerate under in vitro conditions. Hypocotyl and cotyledon explants from 10-d-old seedlings were subcultured onto different callus induction media based on Murashige and Skoog (MS) basal medium supplemented with 1% sucrose and different concentrations and combinations of plant growth regulators. Hypocotyl explants were found to be more suitable for callus induction and organogenesis than cotyledon explants for all cultivars tested. In terms of regeneration, the cv. 'Amager' was significantly more responsive than the other cultivars tested and produced the highest number of shoots/buds per explant. Moreover, among five types of media tested, MS + 8.88 μM 6-benzyloaminopurine (BAP) + 0.53 μM α-naphthylacetic acid (NAA) was most effective for shoot regeneration. Rooting was achieved within 10-15 d on all the rooting media, but MS medium containing 5.37 μM NAA produced the maximum number of strong and healthy roots. Plantlets (95%) were subsequently established in the greenhouse, and no phenotypic variations were observed among regenerated plants. This plant regeneration protocol could be suitable for a wide range of cabbage cultivars.