Seed Health Management for Better Productivity - Govind Ballabh ...

(Seed Health Management for Better Productivity)inhibits the barnase RNAse in barnase-bar/barstar plants. This male sterility/fertility system has showncommercial promise in maize and oilseed rape and can be easily extended to other crop species.Seeds as target for molecular farming:One of the emerging fields of plant biotechnology, referred to as “Molecular Farming”, hasbeen used in recent years to produce value-added products for nutraceuticals, pharmaceuticals,and other industrial applications. Molecular farming is defined as the production of proteins orother metabolites valuable to medicine or industry in plants traditionally used in an agriculturalsetting. The concept of using plants as hosts for the production of valuable proteins has beencalled "molecular farming". A wide range of pharmacologically interesting proteins can beexpressed in diverse plant organs and seeds can be one important host. This has as anadvantage that these transgenic seeds harboring the protein of interest can be stored in the drystate for a long time and the integrity of the pharmacologically interesting protein is kept. Modifiedseeds storage proteins and modified oleosin proteins have been used for this purpose.The accumulation of recombinant antibodies in seeds allows long-term storage at ambienttemperatures because the proteins amass in a stable form. Seeds have the appropriatebiochemical environment for protein accumulation, and achieve this through the creation ofspecialized storage compartments, such as protein bodies and storage vacuoles, which arederived from the secretory pathway. Seeds are also desiccated, which reduces the exposure ofstored proteins to non enzymatic hydrolysis and protease degradation. Cereal seeds also lack thephenolic substances that are present in tobacco leaves, so increasing the efficiency ofdownstream processing. Maize is now the main commercial production crop for recombinantproteins, which reflects advantages such as high biomass yield, ease of transformation and in vitromanipulation, and ease of scale-up. Maize is also being used for the production of recombinantantibodies and further technical/pharmaceutical enzymes, such as laccase, trypsin and aprotinin.The use of barley grains as bioreactors for highly active and thermo-tolerant hybrid cellulase (1,4-ßglucanase) was investigated .Alfalfa and soybean produce lower amounts of leaf biomass than tobacco, but have theadvantage of using atmospheric nitrogen through nitrogen fixation, thereby reducing the need forchemical inputs. Both species have been used to produce recombinant antibodies. Pea is beingdeveloped as a production system, although at present the yields that are possible with thisspecies are low.Seed storage proteins as target for nutritional quality improvements anddevelopment of nutraceuticalsIn general, cereal seed storage proteins are low in lysine and tryptophan while legumes aredeficient in the sulfur containing amino acids, methionine and cysteine and hence can beconsidered as nutritionally poor. Biotechnological approach for improving seed storage proteinquality can be i) protein sequence modification ii) synthetic genes iii) overexpression ofhomologous genes and iv) Transfer and expression of heterologous genes. In order to establishragi as nutraceutical crop, value added products for diabetics, pregnant women and children in theform of breakfast and meals can be prepared based on the scientific rationale explored in our lab.- 194 -