Conservation and Diversity of Seed Associated Endophytes in Zea across Boundaries of Evolution, Ethnography and Ecology

Endophytes are non-pathogenic microbes living inside plants. We asked whether endophytic species were conserved in the agriculturally important plant genus Zea as it became domesticated from its wild ancestors (teosinte) to modern maize (corn) and moved from Mexico to Canada. Kernels from populations of four different teosintes and 10 different maize varieties were screened for endophytic bacteria by culturing, cloning and DNA fingerprinting using terminal restriction fragment length polymorphism (TRFLP) of 16S rDNA. Principle component analysis of TRFLP data showed that seed endophyte community composition varied in relation to plant host phylogeny. However, there was a core microbiota of endophytes that was conserved in Zea seeds across boundaries of evolution, ethnography and ecology. The majority of seed endophytes in the wild ancestor persist today in domesticated maize, though ancient selection against the hard fruitcase surrounding seeds may have altered the abundance of endophytes. Four TRFLP signals including two predicted to represent Clostridium and Paenibacillus species were conserved across all Zea genotypes, while culturing showed that Enterobacter, Methylobacteria, Pantoea and Pseudomonas species were widespread, with γ-proteobacteria being the prevalent class. Twenty-six different genera were cultured, and these were evaluated for their ability to stimulate plant growth, grow on nitrogen-free media, solubilize phosphate, sequester iron, secrete RNAse, antagonize pathogens, catabolize the precursor of ethylene, produce auxin and acetoin/butanediol. Of these traits, phosphate solubilization and production of acetoin/butanediol were the most commonly observed. An isolate from the giant Mexican landrace Mixteco, with 100% identity to Burkholderia phytofirmans, significantly promoted shoot potato biomass. GFP tagging and maize stem injection confirmed that several seed endophytes could spread systemically through the plant. One seed isolate, Enterobacter asburiae, was able to exit the root and colonize the rhizosphere. Conservation and diversity in Zea-microbe relationships are discussed in the context of ecology, crop domestication, selection and migration

Screening for Cellulolytic Plant Enzymes Using Colorimetric and Fluorescence Methods

Cellulolytic activity can be measured using a variety of methods, the choice of which depends on the raw material and goals. An inexpensive, rapid, and reliable method, suitable for plants and other sources alike, is based on digestion of the easily degradable soluble cellulose derivative carboxymethylcellulose (CMC). Direct detection of CMC digestion by cellulolytic activity is based on the “negative staining principle,” where undigested CMC is stained with appropriate colorimetric or fluorescent stains, while CMC exposed to digestion by cellulase shows a reduction in staining intensity. The reduction is proportional to the enzyme activity and is not influenced by endogenous levels of glucose in the sample, making this method applicable for a wide variety of samples, including plant material

Bacterial Diversity in Cold Environments of Indian Himalayas

Not AvailableThe remote cold environments of Indian Himalayas are witnessed by extreme situations with a lot of variations in temperatures, low availability of water and nutrients and exposure to a lot of radiations. These extreme environments generally considered unfavourable to growth and survival of plants and animals are usually colonized by the microorganisms capable of growth and survivability under the prevailing severe conditions. Because of the extremophilic enzymes, proteins and biomolecules possessed by cold-adapted microorganism, they are of importance for industry, agriculture and biotechnology. In this chapter, (1) diversity of bacteria present in cold environments based on culturing and metagenomics approaches, (2) microorganisms from cold environments in agriculture, (3) novel bacteria from cold environments and (4) genome sequencing of bacteria from cold environments have been discussed. Bacteria affiliated to various phyla like Proteobacteria, Firmicutes, Actinobacteria, Bacteroidetes, Acidobacteria, Gemmatimonadetes, Planctomycetes, Chlamydiae, Chlorobi, Chloroflexi, Dictyoglomi, Fibrobacteres, Nitrospirae and Verrucomicrobia have been reported from the Indian Himalayas. Microorganisms belonging to various genera for improving agriculture production under cold environment have been isolated and identified. Twenty-one novel species of bacteria have been isolated from different locations in the cold environments of the Himalayas. A genome of 18 strains isolated from these cold environments has been sequenced and published.Not Availabl