In flowering plants, pollen wall is a specialized extracellular cell-wall matrix surrounding male gametophytes and acts as a natural protector of pollen grains against various environmental and biological stresses. The formation of pollen wall is a complex but well-regulated process, which involves the action of many different genes. However, the genetic and molecular mechanisms underlying this process remain largely unknown.In this study, we isolated and characterized a novel rice male sterile mutant, defective pollen wall3 (dpw3), which displays smaller and paler anthers with aborted pollen grains. DPW3 encodes a novel membrane-associated alpha integrin-like protein conserved in land plants. DPW3 is ubiquitously expressed in anther developmental stages and its protein is localized to the plasma membrane, endoplasmic reticulum (ER) and Golgi.Anthers of dpw3 plants exhibited unbalanced anther cuticular profile, abnormal Ubisch bodies, disrupted callose deposition, defective pollen wall formation such as abnormal microspore plasma membrane undulation and defective primexine formation, resulting in pollen abortion and complete male sterility.Our findings revealed a novel and vital role of alpha integrin-like proteins in plant male reproduction.

Rice (Oryza sativa L.) MADS3 transcription factor regulates the homeostasis of reactive oxygen species (ROS) during late anther development, and one MADS3 mutant, mads3-4, has defective anther walls, aborted microspores and complete male sterility. Here, we report the untargeted metabolomic analysis of both wild type and mads3-4 mature anthers. Mutation of MADS3 led to an unbalanced redox status and caused oxidative stress that damages lipid, protein, and DNA. To cope with oxidative stress in mads3-4 anthers, soluble sugars were mobilized and carbohydrate metabolism was shifted to amino acid and nucleic acid metabolism to provide substrates for the biosynthesis of antioxidant proteins and the repair of DNA. Mutation of MADS3 also affected other aspects of rice anther development such as secondary metabolites associated with cuticle, cell wall, and auxin metabolism. Many of the discovered metabolic changes in mads3-4 anthers were corroborated with changes of expression levels of corresponding metabolic pathway genes. Altogether, this comparative metabolomic analysis indicated that MADS3 gene affects rice anther development far beyond the ROS homeostasis regulation.Keywords: Anther; ascorbate; cysteine/cysteine; glutathione/oxidized glutathione; Oryza. sativa L; secondary metabolism Citation: Qu G, Quan S, Mondol P, Xu J, Zhang D, Shi J (2014) Comparative metabolomic analysis of wild type and mads3 mutant rice anthers.

This study was aimed at investigating the physico-chemical and microbial diversity for rapid composting of sugarcane press mud (PM) leading to organic manure. Five bacterial strains (Cellulomonas sp., Klebsiella sp., Proteus sp., Enterobacter sp., Salmonella sp.) were tested under in vivo conditions for bioconversion of PM using pile method. Results revealed that combined inoculation of bacterial consortia was found to be the best decomposer of PM resulting reduction of organic carbon content (26.75%), C:N ratio (12.44%). In parallel, it increased the nitrogen (2.34%), phosphorous (1.15%) and potassium (1.37%) content along with the population of microorganisms i.e. bacteria, fungi and actinomycetes. However, the population of tested bacteria was gradually depleted after completion of PM decomposition together with pathogenic bacteria and fungi due to full conversion of carbon component into other minerals, i.e. N, P, K etc. Taken together, these findings certainly pinpoints the effective role of bacterial suspension for composting sugarcane press mud which the eventually be used as organic manure.

A competent and reproducible practice for the invitro shoot regeneration of Cucurbita maxima,C.pepo and Cucumissativus was developed from various explants through direct and indirect organogenesis.InC. maxima, between cotyledon and leaf segment, cotyledon was found to be most responsive for callus induction in MS medium augmented with 0.5 mg·L-1 2,4 dichlorophenoxy acetic acid (2,4-D) plus 100 mg·L-1 casein hydrolysate and 0.5 mg·L-1 2,4-D plus 15% coconut water and for leaf segment it was on MS medium containing 2.5 mg·L-1 2,4-D. Comparing the 2 explants it was found that leaf segment was most suitable for callus induction in C. maxima. For massive multiplication of C. pepomericlones shoot tip and nodal cutting were used. MS medium containing 3.0 mg·L-1 6-benzyl aminopurine plus 0.5 mg·L-1gibberellic acid (GA3) was found most effective for shoot regeneration and 1.0 mg·L-1 IBA was found most effective for rooting. In this trait cv. Bulum was more responsive than cv. Rumbo. On the other hand, to generate virus free plantlets of C. sativus, different concentrations of kinetin were used, and 1.5 mg·L-1 KIN shown the best performance for primary culture establishment. For shoot multiplication, 1.0 mg·L-1 BAP and 2.0 mg·L-1 BAP plus 0.5 mg·L-1 KIN containing medium shown best result. Subsequently, 2.0 mg·L-1 BAP plus 0.5 mg·L-1 KIN was best composition for root induction. Our report demonstrated comprehensive protocols and variability in explants, growth regulator response in shoot regeneration potential of in different cucurbit plants.

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