Harnessing leaf photosynthetic traits and antioxidant defence for multiple stress tolerance in three premium indigenous rice landraces of Jeypore tract of Odisha, India.

The aim of the present research was to compare the effects of different abiotic stresses (drought, salinity and submergence) on growth, photosynthesis and PSII activity along with antioxidant defence of three premium rice landraces, namely Kalajeera, Machhakanta and Haladichudi from Jeypore tract of Odisha, India to evaluate their performance under multiple stresses and possibility of using in the pre-breeding programs. Results showed that drought, salinity and submergence significantly reduced plant growth, leaf photosynthesis, water use efficiency (WUE), carboxylation efficiency (CE), PSII activity and SPAD chlorophyll index, and the highest effect was observed in susceptible check variety (IR64). In addition, the indigenous rice lines showed better stomatal traits such as stomatal density (SD), stomatal size (SS) and stomatal number per leaf area (S/LA). Notably, higher activities of antioxidative enzymes and proline accumulation was observed in studied indigenous rice landraces and were found comparable with the drought and salinity tolerant (N22) and submergence tolerant (FR13A) check varieties. Based on our findings it was revealed that these landraces can be expected to possess an adequate level of tolerance to drought, salinity and submergence and showed adaptive fitness to multiple stresses during seedling stage. These landraces can be considered as potential donor for future rice pre-breeding program.

Data assessing genotypic variations in selected traditional rice landraces of Jeypore tract of Odisha, India based on photosynthetic traits.

Variations in photosynthetic characteristics and dry matter accumulation were investigated in thirty selected rice (Oryza sativa L.) landraces from Jeypore tract of Odisha, India to find the possibility of their use in crop improvement programs. Leaf gas exchange measurements, photosystem (PS) II activity and leaf pigment estimates were conducted at the flowering stage. Significant differences were noticed in the CO2 photosynthetic rate (PN), stomatal conductance (gs), transpiration rate (E), internal CO2 concentration (Ci), water use efficiency (WUE) and carboxylation efficiency (CE) among the landraces. In addition, significant variation was observed in leaf chlorophyll content, PS II activity and dry matter accumulation (DMA). Further, multiple correlations between photosynthetic characteristics and other physiological traits revealed that leaf photosynthesis was not significantly influenced by PS II photochemical activity, leaf area and pigment contents but it was regulated by stomatal conductance, water use efficiency and carboxylation efficiency. Taken together, data presented here shows that some of the landraces had superior photosynthetic traits along with better DMA under prevailing environmental condition and can be used for future crop improvement programs aimed for an increase of leaf photosynthesis in rice.

Data on genetic potentiality of folk rice (Oryza sativa L.) genotypes from Koraput, India in reference to drought tolerance traits.

Precise physiological and molecular marker-based assessment provides information about the extent of genetic diversity, which helps for effective breeding programmes. We have conducted detailed physiological and molecular marker-based assessment of selected eight indigenous rice landraces from Koraput, India along with tolerant (N22) and susceptible (IR64) check varieties under control and simulated drought stress using polyethylene glycol (PEG) 6000. After exposure to different levels of drought stress, relative germination performance (RGP), seedling vigour index (SVI) and relative growth index (RGI) were significantly declined in all the rice landraces compared to the control plants and significant varietal differences were observed. Genetic relationship among the studied rice landraces was assessed with 24 previously reported drought tolerance linked Simple Sequence Repeat (SSR) markers. A total of 53 alleles were detected at the loci of the 24 markers across the 10 rice accessions. The Nei's gene diversity (He) and the polymorphism information content (PIC) ranged from 0 to 0.665 and 0 to 0.687, respectively. Six SSR loci, RM276, RM411, RM3, RM263, RM216 and RM28199, provided the highest PIC values and are potential for exploring the genetic diversity of studied rice lines for drought tolerance. Four rice genotypes (Butkichudi, Haldichudi, Machakanta and Kalajeera) showed the highest genetic distance with tolerant check variety (N22) and can be considered as valuable genetic resources for drought breeding program.

Physiological characterization and allelic diversity of selected drought tolerant traditional rice (Oryza sativa L.) landraces of Koraput, India.

Water-deficit stress tolerance in rice is important for maintaining stable yield, especially under rain-fed ecosystem. After a thorough drought-tolerance screening of more than 130 rice genotypes from various regions of Koraput in our previous study, six rice landraces were selected for drought tolerance capacity. These six rice landraces were further used for detailed physiological and molecular assessment under control and simulated drought stress conditions. After imposing various levels of drought stress, leaf photosynthetic rate (PN), photochemical efficiency of photosystem II (Fv/Fm), SPAD chlorophyll index, membrane stability index and relative water content were found comparable with the drought-tolerant check variety (N22). Compared to the drought-susceptible variety IR64, significant positive attributes and varietal differences were observed for all the above physiological parameters in drought-tolerant landraces. Genetic diversity among the studied rice landraces was assessed using 19 previously reported drought tolerance trait linked SSR markers. A total of 50 alleles with an average of 2.6 per locus were detected at the loci of the 19 markers across studied rice genotypes. The Nei's genetic diversity (He) and the polymorphism information content (PIC) ranged from 0.0 to 0.767 and 0.0 to 0.718, respectively. Seven SSR loci, such as RM324, RM19367, RM72, RM246, RM3549, RM566 and RM515, showed the highest PIC values and are thus, useful in assessing the genetic diversity of studied rice lines for drought tolerance. Based on the result, two rice landraces (Pandkagura and Mugudi) showed the highest similarity index with tolerant check variety. However, three rice landraces (Kalajeera, Machhakanta and Haldichudi) are more diverse and showed highest genetic distance with N22. These landraces can be considered as the potential genetic resources for drought breeding program.

Genotypic variation of photosynthetic gas exchange and stomatal traits in some traditional rice (Oryza sativa L.) landraces from Koraput, India for crop improvement.

Variations in photosynthetic gas exchange, stomatal traits and photosystem (PS) II activity were investigated in three popular rice (Oryza sativa L.) landraces namely Kalajeera, Machakanta and Haladichudi from Koraput, India and compared with high yielding modern varieties (IR 64 and IR 42) to judge the possibility of using them in crop improvement programmes. The leaf CO2 photosynthetic rate (PN), stomatal conductance (gs), water use efficiency and carboxylation efficiency were significantly higher in traditional landraces as compared to the high yielding variety. In contrast, the transpiration rate, internal CO2 concentration, special analysis device (SPAD) index and chlorophyll were higher in high yielding varieties. In addition, the traditional landraces showed better stomatal traits such as stomatal density (SD), stomatal size (SS) and stomatal index. Further, multiple correlations between different gas-exchange characteristics and other physiological traits revealed that the PN was not dependent on the leaf pigment content or PS II activity. However, it was dependent on stomatal traits like gs, SD and SS. Taken together, the traditional landraces such as Kalajeera, Machakanta and Haladichudi had superior PN and stomatal efficiency compared to the high yielding variety under prevailing environmental condition. Further research is required to elucidate the genetic diversity of these popular landraces compared to high-yielding ones in relation to photosynthesis efficiency for future crop improvement programmes.

Microbial processing of fruit and vegetable wastes into potential biocommodities: a review.

The review focuses on some of the high value-end biocommodities, such as fermented beverages, single-cell proteins, single-cell oils, biocolors, flavors, fragrances, polysaccharides, biopesticides, plant growth regulators, bioethanol, biogas and biohydrogen, developed from the microbial processing of fruit and vegetable wastes. Microbial detoxification of fruit and vegetable processing effluents is briefly described. The advances in genetic engineering of microorganisms for enhanced yield of the above-mentioned biocommodities are elucidated with selected examples. The bottleneck in commercialization, integrated approach for improved production, techno-economical feasibility and real-life uses of some of these biocommodities, as well as research gaps and future directions are discussed.

Effects of different treatments of fly ash and mining soil on growth and antioxidant protection of Indian wild rice.

The aim of the present study was investigation of the effects of fly ash and mining soil on growth and antioxidant protection of two cultivars of Indian wild rice (Oryza nivara and Oryza rufipogon) for possible phytoremediation and restoration of metal-contaminated site. In this study, Indian wild rice showed significant changes in germination, growth, and biochemical parameters after exposure to different ratio of fly ash and mining soil with garden soil. There was significant reduction of germination, fresh weight, dry weight, leaf chlorophyll content, leaf area, Special Analysis Device Chlorophyll (SPAD) Index, proteins, and activities of antioxidant enzymes in both cultivars of the wild rice grown in 100% fly ash and mining soil compared to the plants grown in 100% garden soil. Results from this study showed that in both cultivars of wild rice, all growth and antioxidant parameters increased when grown in 50% fly ash and mining soil. Taken together, Indian wild rice has the capacity to tolerate 50% of fly ash and mining soil, and can be considered as a good candidate for possible phytoremediation of contaminated soils.

Microbial-processing of fruit and vegetable wastes for production of vital enzymes and organic acids: Biotechnology and scopes.

Wastes generated from fruits and vegetables are organic in nature and contribute a major share in soil and water pollution. Also, green house gas emission caused by fruit and vegetable wastes (FVWs) is a matter of serious environmental concern. This review addresses the developments over the last one decade on microbial processing technologies for production of enzymes and organic acids from FVWs. The advances in genetic engineering for improvement of microbial strains in order to enhance the production of the value added bio-products as well as the concept of zero-waste economy have been briefly discussed.