Biosensors: A Fast-Growing Technology for Pathogen Detection in Agriculture and Food Sector

Agriculture and food have a greater role to play in order to achieve sustainable development goals. Therefore, there is a need to put an end to the effect of pathogens on food quality and safety. Pathogens have been recognized as one of the major factors causing a reduction in profitable food production. The conventional methods of detecting pathogens are time-consuming and expensive for the farmers in rural areas. In view of this, this chapter reviews the biosensors that have been developed for the detection of biological hazards in food and agricultural sectors. This chapter also lays emphasis on the impact of nanotechnology on building a fast, reliable, more sensitive, accessible, user-friendly and easily adaptable technology for illiterate farmers in the rural communities. On the whole, we have addressed the past and most recent biosensors that could ensure the quick delivery of vision 2030 which aims to end hunger and poverty

Effect of glyphosate on the activity of DAHP synthase isozymes in callus cultures of groundnut (<i>Arachis hypogaea </i>L.) selected <i>in vitro</i>

235-240Two isozymes of 3-deoxy-D-arabino-heptulosonate-7-phosphate synthase (DAHP synthase or DS, EC 4.1.2.15) from the callus cultures of Arachis hypogaea L. were resolved by DEAE cellulose column chromatography and characterized using selective assays based on divalent cation requirements and regulation by the end-product amino acids. The total extractable activity of DAHP synthase did not show any change in the glyphosate sensitive and tolerant cell lines when compared to 5-enolpyruvylshikimate-3-phosphate synthase (EPSP synthase, EC 2.5.1.19), the known target of inhibition by glyphosate. However, the activities of both, DAHP synthase and EPSP synthase were inhibited by glyphosate in vitro. The inhibitory effects of glyphosate on the activities of (a) EPSP synthase and DAHP synthase, and (b) isozymes of DAHP synthase, have been compared. The data indicate that the Co2+ dependent isozyme of DAHP synthase is a putative target for the action of glyphosate in A. hypogaea.</i

Regeneration of pigeonpea (Cajanus cajan) from cotyledonary node via multiple shoot formation

Plant regeneration, which is the major limiting factor for transformation of Cajanus cajan, has been obtained via multiple shoot formation from the cotyledonary node region of seedlings germinated on MS medium containing 2 mgl<SUP>-1</SUP> 6-benzylaminopurine. A mass of multiple shoot-initials formed at the axillary bud region of the cotyledonary node of the seedlings within two weeks. The cotyledonary node along with the mass of shoot-initials excised from the seedling, continued to form new shoot-initials on MS medium containing 6-benzylaminopurine (2 mgl<SUP>-1</SUP>) and supplemented topically with indole-3-acetic acid. The formation of new shoot-initials was also observed from the cotyledonary nodal explant, after cutting off its surface layers to completely remove the pre-existing shoot-initials and culturing it on 6-benzylaminopurine (2 mgl<SUP>-1</SUP>) containing medium. The shoots elongated rapidly on basal MS medium and rooted efficiently in MS medium supplemented with indole-3-butyric acid (0.5 mgl<SUP>-1</SUP>). The procedure described is efficient, and highly reproducible and a common response was observed for all the six varieties tested

Induction and differentiation of callus from embryos of Cocos nucifera L. by IAA-conjugates

Calli from young embryos of Cocos nucifera L. were induced on B5 medium supplemented with IAA-conjugates (IAA-asp or IAA-ala) at a concentration of 2.0 mg/1 and callusing was increased by about 10% if both IAA-conjugates, IAA-asp and IAA-ala were added together. Differentiation of shoots and roots was achieved by transferring calli to B5 medium supplemented with either IAA-asp (2.0 mg/1)+Kn(2.0 mg/1) or NAA (2.0 mg/1). Complete plantlets were obtained on B5 medium supplemented with NAA (0.5 mg/1)+BAP (2.0 mg/1)+PVP (1.0 g/1)

The molecular basis of morphogenesis in plants: the making of the Arabidopsis flower

Morphogenesis is a subject that has attracted the attention of plant biologists for long. The development of tissue culture technique - combined with the discovery and use of various plant hormones - enabled differentiation of calli into plantlets with normal roots, stems and leaves, and serves as the base of modern plant biotechnology. Nevertheless, a deeper insight into the genetic basis of morphogenesis has been gained only in the last decade or so. The isolation of the first homeotic genes in Drosophila in the eighties, spurred new interest in studying the molecular basis of homeotic transformation, known in plants for more than a century. This article traces the beginning of work on homeotic genes in Antirrhinum. In the nineties, however, work on Arabidopsis gained rapid momentum. Accordingly, studies on the development of the Arabidopsis flower leading to the isolation of genes such as AGAMOUS, APETALA 1, 2 and 3, PISTILLATA and LEAFY are discussed in greater detail. Homeotic genes control the expression of many ordinary genes downstream; however, often homeotic genes themselves are under hierarchical control of other homeotic genes upstream. Also touched upon briefly is the usefulness of these studies to biotechnology

Cloning and characterization of a mitochondrial glyoxalase II from Brassica juncea that is upregulated by NaCl, Zn, and ABA

A cDNA (1061 bp) Bj glyII was cloned from a mannitol induced library of Brassica juncea. It encoded a protein of 335 amino acids with a molecular weight of 36.52 kDa. The deduced amino acid sequence of the clone showed 92% and 56% identity with Pennisetum and rice glyoxalase II, respectively, and 30% identity was observed with the human glyoxalase II. Search for the identical residues revealed the presence of highly conserved THHHXDH domain which is involved in zinc binding. p-NN and pSORT analysis of this sequence revealed a N-terminal mitochondrial target peptide. The cDNA was cloned in pMAL and a fusion protein with MBP (78 kDa) was expressed in Escherichia coli. The recombinant protein was purified approximately sixfold by affinity purification on amylose column and showed its pH optima at 7.0. The Km was determined to be 120 μM using S-d-lactoylglutathione as substrate. The expression of Bj glyII under various abiotic stress conditions showed that it is upregulated by salinity, heavy metal stress, and ABA