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Thirty different wheat genotypes, including landraces, cultivars, and related wild species, were analyzed for puroindoline genes and proteins. Full-length Pina and Pinb genes were amplified using gene-specific markers where 13 genotypes amplified both genes, while 17 genotypes had either one or none of the puroindoline genes. None of the puroindoline genes were detected in any of the Triticum durum cultivars. Genotypes with both puroindoline genes had a soft grain texture, while other genotypes had hard grains. Related nonprogenitor species with A, C, M, U, and S genomes also showed the presence of either one or both the puroindoline genes, indicating that these species can also be utilized for development of extra-soft wheat. SDS-PAGE analysis of selected wheat genotypes revealed that puroindoline proteins are approximately 13-14 kDa and the protein results were in agreement with the PCR results. Puroindoline proteins of selected 3 soft wheat genotypes HPW 89, Naphal, and IITR-9 also exhibited antimicrobial activity against gram-positive and gram-negative bacteria. Both genes of a soft wheat cultivar, HPW 89, were successfully cloned in the Escherichia coli DH-5 $\alpha$ strain. Introgression and molecular characterization of diverse Pina and Pinb genes to develop extra-soft wheat is in progress.

The role of oxidative stress management was evaluated in two maize (Zea mays L.) genotypes - Parkash (drought-resistant) and Paras (drought-sensitive), subjected to drought stress during reproductive stage. Alterations in their antioxidant pools - glutathione (GSH) and ascorbic acid (AsA) combined with activities of enzymes glutathione reductase (GR), ascorbate peroxidase (APX), peroxidase (POX) and catalase (CAT) involved in defense against oxidative stress and stress parameters, namely chlorophyll (Chl), hydrogen peroxide (H2O2) and malondialdehyde (MDA) were investigated in flag leaves from silk emergence till maturity. The drought caused transient increase in GR, APX, POX and CAT activities in drought-tolerant genotype (Parkash) which decreased at later stages with the extended period of drought stress. However, in Paras, drought stress caused decrease in activities of GR and CAT from initial period of stress till the end of experiment, except for POX which showed slight increase in activity. A significant increase in GSH content was observed in Parkash till 35 days after silking (DAS), whereas in Paras, GSH content remained lower than irrigated till maturity. Parkash which had higher AsA and Chl contents, also showed lower H2O2 and MDA levels than Paras under drought stress conditions. However, at the later stages, decline in antioxidant enzyme activities in Parkash due to severe drought stress led to enhanced membrane damage, as revealed by the accumulation of MDA. Our data indicated that significant activation of antioxidant system in Parkash might be responsible for its drought-tolerant behavior under drought stress and helped it to cope with the stress up to a definite period. Thus, the results indicate that antioxidant status and lipid peroxidation in flag leaves can be used as indices of drought tolerance in maize plants and also as potential biochemical targets for the crop improvement programmes to develop drought-tolerant cultivars.

Fifteen days old seedlings of waterlogging tolerant (Parkash) and sensitive (Paras) maize genotypes were subjected to short-term waterlogging (18 h) under field conditions. Activities of various antioxidative and anaerobic metabolism enzymes were investigated in leaf and root tissues. Superoxide dismutase (SOD) activity increased in leaf tissue while glutathione reductase (GR) activity was enhanced in leaf as well as root in both the genotypes. However, tolerant genotype had better induction capability of SOD and GR in roots in comparison with sensitive genotype. Catalase activity increased in roots of both genotypes. Waterlogging caused strong induction in alcohol dehydrogenase activity in the roots of Paras and Parkash under stress conditions. Aldehyde dehydrogenase activity was significantly increased only in roots of Parkash in response to waterlogging. In comparison with sensitive genotype, the tolerant genotype had low H2O2 and malondialdehyde content in roots under stress conditions. The present studies suggested that tolerant genotype had a greater protective ability due to higher induced activities of antioxidant and ethanolic fermentation systems than Paras.

The present investigation was undertaken to identify the possible mode of mechanism that could provide tolerance to maize (Zea mays L.) seedlings under waterlogging. Using cup method, a number of maize genotypes were screened on the basis of survival of the seedlings kept under waterlogging. Two tolerant (LM5 and Parkash) and three susceptible (PMH2, JH3459 and LM14) genotypes were selected for the present study. Activities of antioxidant and ethanolic fermentation enzymes and content of hydrogen peroxide (H2O2), glutathione and ascorbic acid were determined in roots of these genotypes after 72 h of waterlogging. Waterlogging treatment caused decline in activities of superoxide dismutase (SOD), catalase (CAT) and ascorbate peroxidase (APX) in all the genotypes. However, only susceptible genotypes showed slight increase in glutathione reductase (GR) activity. Significant reduction in APX/GR ratio in susceptible genotypes might be the cause of their susceptibility to waterlogging. The tolerant seedlings had higher GR activity than susceptible genotypes under unstressed conditions. Stress led to decrease in H202 and increase in glutathione content of both tolerant and susceptible genotypes, but only tolerant genotypes exhibited increase in ascorbic acid under waterlogging conditions. In the tolerant genotypes, all the enzymes of anaerobic metabolism viz. alcohol dehydrogenase (ADH), aldehyde dehydrogenase (ALDH) and pyruvate decarboxylase (PDC) were upregulated under waterlogging, whereas in susceptible genotypes, only ADH was upregulated, suggesting that efficient upregulation of entire anaerobic metabolic machinery is essential for providing tolerance against waterlogging. The study provides a possible mechanism for waterlogging tolerance in maize.

Seedlings of selected six genotypes of maize (Zea mays L.) differing in their drought sensitivity (LM5 and Parkash drought-tolerant and PMH2, JH3459, Paras and LM14 as drought-sensitive) were exposed to 72 h drought stress at two leaf stage. Alterations in their antioxidant pools combined with activities of enzymes involved in defense against oxidative stress were investigated in leaves. Activities of some reactive oxygen species (ROS)-scavenging enzymes, catalase (CAT) and ascorbate peroxidase (APX) were enhanced in tolerant genotypes in response to drought stress. Superoxide dismutase (SOD) activity was significantly decreased in sensitive genotypes, but remained unchanged in tolerant genotypes under stress. Peroxidase (POX) activity was significantly induced in tolerant, as well as sensitive genotypes. Imposition of stress led to increase in H2O2 and malondialdehyde (MDA, a marker for lipid peroxidation) content in sensitive genotypes, while in tolerant genotypes no change was observed. Significant increase in glutathione content was observed in sensitive genotypes. Ascorbic acid pool was induced in both tolerant and sensitive genotypes, but induction was more pronounced in tolerant genotypes. Significant activation of antioxidative defence mechanisms correlated with drought-induced oxidative stress tolerance was the characteristic of the drought tolerant genotypes. These studies provide a mechanism for drought tolerance in maize seedlings.