de novo transcriptomic profiling of differentially expressed genes in grass halophyte Urochondra setulosa under high salinity

Soil salinity is one of the major limiting factors for crop productivity across the world. Halophytes have recently been a source of attraction for exploring the survival and tolerance mechanisms at extreme saline conditions. Urochondra setulosa is one of the obligate grass halophyte that can survive in up to 1000 mM NaCl. The de novo transcriptome of Urochondra leaves at different salt concentrations of 300–500 mM NaCl was generated on Illumina HiSeq. Approximately 352.78 million high quality reads with an average contig length of 1259 bp were assembled de novo. A total of 120,231 unigenes were identified. On an average, 65% unigenes were functionally annotated to known proteins. Approximately 35% unigenes were specific to Urochondra. Differential expression revealed significant enrichment (P < 0.05) of transcription factors, transporters and metabolites suggesting the transcriptional regulation of ion homeostasis and signalling at high salt concentrations in this grass. Also, about 143 unigenes were biologically related to salt stress responsive genes. Randomly selected genes of important pathways were validated for functional characterization. This study provides useful information to understand the gene regulation at extremely saline levels. The study offers the first comprehensive evaluation of Urochondra setulosa leaf transcriptome. Examining non-model organisms that can survive in harsh environment can provide novel insights into the stress coping mechanisms which can be useful to develop improved agricultural crops.

Comparative study of fodder halophytes in saline and alkaline soils

A research was conducted in 2014-15 to know the usefulness of halophytes on saline and sodic stress with 3 halophytes and 6 treatments i.e Control (pH-7.0 and ECe-0.56), Sodic (pH-9.5 and 10.0) and Saline (ECe- 15, 25 and 35 dSm-1) which was done in Factorial randomized block design in small micro-plots in research area at Central Soil Salinity Research Institute, Karnal, Haryana. We found that pHs of soils were less and ECe of soils were more affected by growing halophytes in this experiment. Dicanthium had more number of tillers and Suaeda had more number of branches under sodic stress. In case of Urochondra Setulosa, number of tillers had increased up to pH-9.5 thereafter it decreased. Likewise, all other plant nutrients concentration in the soil was found to be reduced which showed that halophytes utilized these nutrients for their growth under the stress conditions. the results showed that Dicanthuim annulatum can be grown as a fodder crop under low to high sodic stress conditions whereas Suaeda nudiflora and Urochondra setulosa can be grown easily under saline soils/ irrigated condtions and in areas with sea water.

Morphometric Variations in Caryopses and Seedlings of Two Grass Species Growing Under Contrasting Habitats

Urochondra setulosa grows in marine conditions, while Sporobolus indicus grows near fresh water and sometimes also close to moist places along roadside areas. Both species belong to the same tribe and same family. The two grass species growing under different habitats showed characteristic variations in their morphometric traits of the caryopsis and seedlings. U. setulosa growing in salty area had characteristic features, e.g. leaf and culm with salt deposition, rigid leaf blade with pointed leaf tip, while S. indicus growing near fresh water showed glabrous nodes and internodes. Morphometric analysis of caryopses of both species showed very similar features, without prominent differences in their length, breadth and thickness. But light microscopy and scanning electron microscopic (SEM) studies showed variations. Under light microscopy, features like colour, shape and compression of caryopses showed differences among the species. SEM studies of caryopses revealed a reticulate type of pattern of sculpturing on both dorsal and ventral surfaces, whereas anticlinal and periclinal walls in U. setulosa were elevated with folded walls, while in S. indicus had non elevated undulating walls. In conclusion, each individual grass ecotype evolves some characteristic morphological features to thrive well under a particular environment. Both species studied hereby, grown in different habitats, showed remarkable differentiations in their characters, thus indicating that habitats play a major role in traits of the plant growth.