Machine Learning Heuristics on Gingivobuccal Cancer Gene Datasets Reveals Key Candidate Attributes for Prognosis.

Delayed cancer detection is one of the common causes of poor prognosis in the case of many cancers, including cancers of the oral cavity. Despite the improvement and development of new and efficient gene therapy treatments, very little has been carried out to algorithmically assess the impedance of these carcinomas. In this work, from attributes or NCBI's oral cancer datasets, viz. (i) name, (ii) gene(s), (iii) protein change, (iv) condition(s), clinical significance (last reviewed). We sought to train the number of instances emerging from them. Further, we attempt to annotate viable attributes in oral cancer gene datasets for the identification of gingivobuccal cancer (GBC). We further apply supervised and unsupervised machine learning methods to the gene datasets, revealing key candidate attributes for GBC prognosis. Our work highlights the importance of automated identification of key genes responsible for GBC that could perhaps be easily replicated in other forms of oral cancer detection.

Genome-wide identification and multiple abiotic stress transcript profiling of potassium transport gene homologs in Sorghum bicolor.

Potassium (K+) is the most abundant cation that plays a crucial role in various cellular processes in plants. Plants have developed an efficient mechanism for the acquisition of K+ when grown in K+ deficient or saline soils. A total of 47 K+ transport gene homologs (27 HAKs, 4 HKTs, 2 KEAs, 9 AKTs, 2 KATs, 2 TPCs, and 1 VDPC) have been identified in Sorghum bicolor. Of 47 homologs, 33 were identified as K+ transporters and the remaining 14 as K+ channels. Chromosome 2 has been found as the hotspot of K+ transporters with 9 genes. Phylogenetic analysis revealed the conservation of sorghum K+ transport genes akin to Oryza sativa. Analysis of regulatory elements indicates the key roles that K+ transport genes play under different biotic and abiotic stress conditions. Digital expression data of different developmental stages disclosed that expressions were higher in milk, flowering, and tillering stages. Expression levels of the genes SbHAK27 and SbKEA2 were higher during milk, SbHAK17, SbHAK11, SbHAK18, and SbHAK7 during flowering, SbHAK18, SbHAK10, and 23 other gene expressions were elevated during tillering inferring the important role that K+ transport genes play during plant growth and development. Differential transcript expression was observed in different tissues like root, stem, and leaf under abiotic stresses such as salt, drought, heat, and cold stresses. Collectively, the in-depth genome-wide analysis and differential transcript profiling of K+ transport genes elucidate their role in ion homeostasis and stress tolerance mechanisms.

Intriguing Role of Proline in Redox Potential Conferring High Temperature Stress Tolerance.

Proline is a proteinogenic amino acid synthesized from glutamate and ornithine. Pyrroline-5-carboxylate synthetase and pyrroline-5-carboxylate reductase are the two key enzymes involved in proline synthesis from glutamate. On the other hand, ornithine-δ-aminotransferase converts ornithine to pyrroline 5-carboxylate (P5C), an intermediate in the synthesis of proline as well as glutamate. Both proline dehydrogenase and P5C dehydrogenase convert proline back to glutamate. Proline accumulation is widespread in response to environmental challenges such as high temperatures, and it is known to defend plants against unpropitious situations promoting plant growth and flowering. While proline accumulation is positively correlated with heat stress tolerance in some crops, it has detrimental consequences in others. Although it has been established that proline is a key osmolyte, its exact physiological function during heat stress and plant ontogeny remains unknown. Emerging evidence pointed out its role as an overriding molecule in alleviating high temperature stress (HTS) by quenching singlet oxygen and superoxide radicals. Proline cycle acts as a shuttle and the redox couple (NAD+/NADH, NADP+/NADPH) appears to be highly crucial for energy transfer among different cellular compartments during plant development, exposure to HTS conditions and also during the recovery of stress. In this review, the progress made in recent years regarding its involvement in heat stress tolerance is highlighted.

Improvement of small seed for big nutritional feed.

Exploding global population, rapid urbanization, salinization of soils, decreasing arable land availability, groundwater resources, and dynamic climatic conditions pose impending damage to our food security by reducing the grain quality and quantity. This issue is further compounded in arid and semi-arid regions due to the shortage of irrigation water and erratic rainfalls. Millets are gluten (a family of proteins)-free and cultivated all over the globe for human consumption, fuel, feed, and fodder. They provide nutritional security for the under- and malnourished. With the deployment of strategies like foliar spray, traditional/marker-assisted breeding, identification of candidate genes for the translocation of important minerals, and genome-editing technologies, it is now tenable to biofortify important millets. Since the bioavailability of iron and zinc has been proven in human trials, the challenge is to make such grains accessible. This review encompasses nutritional benefits, progress made, challenges being encountered, and prospects of enriching millet crops with essential minerals.

Hevea brasiliensis coniferaldehyde-5-hydroxylase (HbCAld5H) regulates xylogenesis, structure and lignin chemistry of xylem cell wall in Nicotiana tabacum.

KEY MESSAGE: The HbCAld5H1 gene cloned from Hevea brasiliensis regulates the cambial activity, xylem differentiation, syringyl-guaiacyl ratio, secondary wall structure, lignification pattern and xylan distribution in xylem fibres of transgenic tobacco plants. Molecular characterization of lignin biosynthesis gene coniferaldehyde-5-hydroxylase (CAld5H) from Hevea brasiliensis and its functional validation was performed. Both sense and antisense constructs of HbCAld5H1 gene were introduced into tobacco through Agrobacterium-mediated genetic transformation for over expression and down-regulation of this key enzyme to understand its role affecting structural and cell wall chemistry. The anatomical studies of transgenic tobacco plants revealed the increase of cambial activity leading to xylogenesis in sense lines and considerable reduction in antisense lines. The ultra-structural studies showed that the thickness of secondary wall (S2 layer) of fibre had been decreased with non-homogenous lignin distribution in antisense lines, while sense lines showed an increase in S2 layer thickness. Maule color reaction revealed that syringyl lignin distribution in the xylem elements was increased in sense and decreased in antisense lines. The immunoelectron microscopy revealed a reduction in LM 10 and LM 11 labelling in the secondary wall of antisense tobacco lines. Biochemical studies showed a radical increase in syringyl lignin in sense lines without any significant change in total lignin content, while S/G ratio decreased considerably in antisense lines. Our results suggest that CAld5H gene plays an important role in xylogenesis stages such as cambial cell division, secondary wall thickness, xylan and syringyl lignin distribution in tobacco. Therefore, CAld5H gene could be considered as a promising target for lignin modification essential for timber quality improvement in rubber.

DnaJs, the critical drivers of Hsp70s: genome-wide screening, characterization and expression of DnaJ family genes in Sorghum bicolor.

The DnaJ/Hsp40s, are important components in the chaperone machine, and play pivotal roles in plant growth, development and stress tolerance. Sorghum, the semi-arid crop, is the drought resilient, model C4 crop. However, no reports of DnaJs have been available. Genome-wide analysis of Sorghum bicolor revealed 113 DnaJ/Hsp40 genes, classified into four groups; 8 genes in SbDnaJ-A class, 10 in SbDnaJ-B, 82 in SbDnaJ-C and 13 in SbDnaJ-D distributed unevenly on all the 10 chromosomes. Chromosomes 1 and 3 were found hot spots with 22 and 20 genes respectively. All genes displayed large number of introns, with an exception of 11 of the SbDnaJ-C which is devoid of introns. Out of 36 paralogous duplications, 7 tandem and 29 segmental duplications were noticed, indicating the major role of segmental duplications in the expansion. Analysis of digital data revealed tissue and stage-specific expressions. Transcriptional profiling of 12 selected genes representing all 4 classes revealed highly significant expression in leaf followed by root tissues. No expression was noticed in stems with an exception of SbDnaJ-C76. The SbDnaJ-A1, D1, and C subgroup genes displayed upregulation in roots, stems and leaves under cold, inferring the involvement of Hsp40s for cellular protection during cold stress. The results demonstrate that C76 and D1 are the candidate genes associated with multiple abiotic stresses. Present research furnishes valuable information about the role of sorghum DnaJs in abiotic stress response and establishes a foundation for understanding the molecular mechanisms associated with plant development and stress tolerance.

Engineering salinity tolerance in plants: progress and prospects.

MAIN CONCLUSION: There is a need to integrate conceptual framework based on the current understanding of salt stress responses with different approaches for manipulating and improving salt tolerance in crop plants. Soil salinity exerts significant constraints on global crop production, posing a serious challenge for plant breeders and biotechnologists. The classical transgenic approach for enhancing salinity tolerance in plants revolves by boosting endogenous defence mechanisms, often via a single-gene approach, and usually involves the enhanced synthesis of compatible osmolytes, antioxidants, polyamines, maintenance of hormone homeostasis, modification of transporters and/or regulatory proteins, including transcription factors and alternative splicing events. Occasionally, genetic manipulation of regulatory proteins or phytohormone levels confers salinity tolerance, but all these may cause undesired reduction in plant growth and/or yields. In this review, we present and evaluate novel and cutting-edge approaches for engineering salt tolerance in crop plants. First, we cover recent findings regarding the importance of regulatory proteins and transporters, and how they can be used to enhance salt tolerance in crop plants. We also evaluate the importance of halobiomes as a reservoir of genes that can be used for engineering salt tolerance in glycophytic crops. Additionally, the role of microRNAs as critical post-transcriptional regulators in plant adaptive responses to salt stress is reviewed and their use for engineering salt-tolerant crop plants is critically assessed. The potentials of alternative splicing mechanisms and targeted gene-editing technologies in understanding plant salt stress responses and developing salt-tolerant crop plants are also discussed.

Genome-wide identification and transcriptional profiling of small heat shock protein gene family under diverse abiotic stress conditions in Sorghum bicolor (L.).

The small heat shock proteins (sHsps/Hsp20s) are the molecular chaperones that maintain proper folding, trafficking and disaggregation of proteins under diverse abiotic stress conditions. In the present investigation, a genome-wide scan revealed the presence of a total of 47 sHsps in Sorghum bicolor (SbsHsps), distributed across 10 subfamilies, the major subfamily being P (plastid) group with 17 genes. Chromosomes 1 and 3 appear as the hot spot regions for SbsHsps, and majority of them were found acidic, hydrophilic, unstable and intron less. Interestingly, promoter analysis indicated that they are associated with both biotic and abiotic stresses, as well as plant development. Sorghum sHsps exhibited 15 paralogous and 20 orthologous duplications. Expression analysis of 15 genes selected from different subfamilies showed high transcript levels in roots and leaves implying that they are likely to participate in the developmental processes. SbsHsp genes were highly induced by diverse abiotic stresses inferring their critical role in mediating the environmental stress responses. Gene expression data revealed that SbsHsp-02 is a candidate gene expressed in all the tissues under varied stress conditions tested. Our results contribute to the understanding of the complexity of SbsHsp genes and help to analyse them further for functional validation.

Genome-wide identification and expression profile analysis of nuclear factor Y family genes in Sorghum bicolor L. (Moench).

Members of the plant Heme Activator Protein (HAP) or NUCLEAR FACTOR Y (NF-Y) are trimeric transcription factor complexes composed of the NF-YA, NF-YB and NF-YC subfamilies. They bind to the CCAAT box in the promoter regions of the target genes and regulate gene expressions. Plant NF-Ys were reported to be involved in adaptation to several abiotic stresses as well as in development. In silico analysis of Sorghum bicolor genome resulted in the identification of a total of 42 NF-Y genes, among which 8 code for the SbNF-YA, 19 for SbNF-YB and 15 for the SbNF-YC subunits. Analysis was also performed to characterize gene structures, chromosomal distribution, duplication status, protein subcellular localizations, conserved motifs, ancestral protein sequences, miRNAs and phylogenetic tree construction. Phylogenetic relationships and ortholog predictions displayed that sorghum has additional NF-YB genes with unknown functions in comparison with Arabidopsis. Analysis of promoters revealed that they harbour many stress-related cis-elements like ABRE and HSE, but surprisingly, DRE and MYB elements were not detected in any of the subfamilies. SbNF-YA1, 2, and 6 were found upregulated under 200 mM salt and 200 mM mannitol stresses. While NF-YA7 appeared associated with high temperature (40°C) stress, NF-YA8 was triggered by both cold (4°C) and high temperature stresses. Among NF-YB genes, 7, 12, 15, and 16 were induced under multiple stress conditions such as salt, mannitol, ABA, cold and high temperatures. Likewise, NF-YC 6, 11, 12, 14, and 15 were enhanced significantly in a tissue specific manner under multiple abiotic stress conditions. Majority of the mannitol (drought)-inducible genes were also induced by salt, high temperature stresses and ABA. Few of the high temperature stress-induced genes are also induced by cold stress (NF-YA2, 4, 6, 8, NF-YB2, 7, 10, 11, 12, 14, 16, 17, NF-YC4, 6, 12, and 13) thus suggesting a cross talk among them. This work paves the way for investigating the roles of diverse sorghum NF-Y proteins during abiotic stress responses and provides an insight into the evolution of diverse NF-Y members.

Isolation and functional characterization of three abiotic stress-inducible (Apx, Dhn and Hsc70) promoters from pearl millet (Pennisetum glaucum L.).

Pearl millet is a C4 cereal crop that grows in arid and semi-arid climatic conditions with the remarkable abiotic stress tolerance. It contributed to the understanding of stress tolerance not only at the physiological level but also at the genetic level. In the present study, we functionally cloned and characterized three abiotic stress-inducible promoters namely cytoplasmic Apx1 (Ascorbate peroxidase), Dhn (Dehydrin), and Hsc70 (Heat shock cognate) from pearl millet. Sequence analysis revealed that all three promoters have several cis-acting elements specific for temporal and spatial expression. PgApx pro, PgDhn pro and PgHsc70 pro were fused with uidA gene in Gateway-based plant transformation pMDC164 vector and transferred into tobacco through leaf-disc method. While PgApx pro and PgDhn pro were active in seedling stages, PgHsc70 pro was active in stem and root tissues of the T2 transgenic tobacco plants under control conditions. Higher activity was observed under high temperature and drought, and less in salt and cold stress conditions. Further, all three promoters displayed higher GUS gene expression in the stem, moderate expression in roots, and less expression in leaves under similar conditions. While RT-qPCR data showed that PgApx pro and PgDhn pro were expressed highly in high temperature, salt and drought, PgHsc70 pro was fairly expressed during high temperature stress only. Histochemical and RT-qPCR assays showed that all three promoters are inducible under abiotic stress conditions. Thus, these promoters appear to be immediate candidates for developing abiotic stress tolerant crops as these promoter-driven transgenics confer high degree of tolerance in comparison with the wild-type (WT) plants.

Genome-scale identification, classification, and tissue specific expression analysis of late embryogenesis abundant (LEA) genes under abiotic stress conditions in Sorghum bicolor L.

Late embryogenesis abundant (LEA) proteins, the space fillers or molecular shields, are the hydrophilic protective proteins which play an important role during plant development and abiotic stress. The systematic survey and characterization revealed a total of 68 LEA genes, belonging to 8 families in Sorghum bicolor. The LEA-2, a typical hydrophobic family is the most abundant family. All of them are evenly distributed on all 10 chromosomes and chromosomes 1, 2, and 3 appear to be the hot spots. Majority of the S. bicolor LEA (SbLEA) genes are intron less or have fewer introns. A total of 22 paralogous events were observed and majority of them appear to be segmental duplications. Segmental duplication played an important role in SbLEA-2 family expansion. A total of 12 orthologs were observed with Arabidopsis and 13 with Oryza sativa. Majority of them are basic in nature, and targeted by chloroplast subcellular localization. Fifteen miRNAs targeted to 25 SbLEAs appear to participate in development, as well as in abiotic stress tolerance. Promoter analysis revealed the presence of abiotic stress-responsive DRE, MYB, MYC, and GT1, biotic stress-responsive W-Box, hormone-responsive ABA, ERE, and TGA, and development-responsive SKn cis-elements. This reveals that LEA proteins play a vital role during stress tolerance and developmental processes. Using microarray data, 65 SbLEA genes were analyzed in different tissues (roots, pith, rind, internode, shoot, and leaf) which show clear tissue specific expression. qRT-PCR analysis of 23 SbLEA genes revealed their abundant expression in various tissues like roots, stems and leaves. Higher expression was noticed in stems compared to roots and leaves. Majority of the SbLEA family members were up-regulated at least in one tissue under different stress conditions. The SbLEA3-2 is the regulator, which showed abundant expression under diverse stress conditions. Present study provides new insights into the formation of LEAs in S. bicolor and to understand their role in developmental processes under stress conditions, which may be a valuable source for future research.

The vacuolar proton pyrophosphatase gene (SbVPPase) from the Sorghum bicolor confers salt tolerance in transgenic Brahmi [Bacopa monnieri (L.) Pennell].

Plants overcome the effect of Na+ toxicity either by excluding Na+ at the plasma membrane or by sequestering them into the vacuoles. Influx of Na+ ions into the plant vacuoles is usually driven by H+ generated by vacuolar-type H+-ATPase as well as vacuolar proton pyrophosphatse (VPPase). In the present study, we have developed Bacopa monnieri transgenics via Agrobacterium tumefaciens containing the recombinant vector pCAMBIA2300-SbVPPase gene. Transformants were produced using nodal explants. Transformants were confirmed by PCR and DNA blot analysis. qPCR analysis showed higher transcript levels of SbVPPase compared to untransformed control (UC). Higher VPPase activity was recorded in transgenics compared to UC. Under 150 mM salt stress, transgenic shoots showed enhanced Na+ accumulation with better biomass production, increased glycine betaine content, and total soluble sugar levels than UC. Transgenic shoots showed 2.9-3.8-folds lower levels of malondialdehyde content indicating lesser membrane damage. Increase in antioxidant enzyme activities (1.4-3.2-folds) was observed in transgenics compared to UC. Transgenics also displayed 7.3-9.0-folds enhanced accumulation of the medicinally important compound bacoside A. Increased biomass production, accumulation of Na+, osmolytes (glycine betaine, sugars etc.), and elevated antioxidant enzyme activities indicate better osmotic adjustment in transgenics by compartmentalization of Na+ into the vacuoles under salt stress conditions. Thus, overexpression of SbVPPase in Bacopa alleviated salt stress by sequestering Na+.

Genome-Wide Identification and Analysis of Arabidopsis Sodium Proton Antiporter (NHX) and Human Sodium Proton Exchanger (NHE) Homologs in Sorghum bicolor.

Na⁺ transporters play an important role during salt stress and development. The present study is aimed at genome-wide identification, in silico analysis of sodium-proton antiporter (NHX) and sodium-proton exchanger (NHE)-type transporters in Sorghum bicolor and their expression patterns under varied abiotic stress conditions. In Sorghum, seven NHX and nine NHE homologs were identified. Amiloride (a known inhibitor of Na⁺/H⁺ exchanger activity) binding motif was noticed in both types of the transporters. Chromosome 2 was found to be a hotspot region with five sodium transporters. Phylogenetic analysis inferred six ortholog and three paralog groups. To gain an insight into functional divergence of SbNHX/NHE transporters, real-time gene expression was performed under salt, drought, heat, and cold stresses in embryo, root, stem, and leaf tissues. Expression patterns revealed that both SbNHXs and SbNHEs are responsive either to single or multiple abiotic stresses. The predicted protein⁻protein interaction networks revealed that only SbNHX7 is involved in the calcineurin B-like proteins (CBL)- CBL interacting protein kinases (CIPK) pathway. The study provides insights into the functional divergence of SbNHX/NHE transporter genes with tissue specific expressions in Sorghum under different abiotic stress conditions.

Genome-Wide Identification, Characterization, and Expression Analysis of Small RNA Biogenesis Purveyors Reveal Their Role in Regulation of Biotic Stress Responses in Three Legume Crops.

Biotic stress in legume crops is one of the major threats to crop yield and productivity. Being sessile organisms, plants have evolved a myriad of mechanisms to combat different stresses imposed on them. One such mechanism, deciphered in the last decade, is small RNA (sRNA) mediated defense in plants. Small RNAs (sRNAs) have emerged as one of the major players in gene expression regulation in plants during developmental stages and under stress conditions. They are known to act both at transcriptional and post-transcriptional levels. Dicer-like (DCL), Argonaute (AGO), and RNA dependent RNA polymerase (RDR) constitute the major components of sRNA biogenesis machinery and are known to play a significant role in combating biotic and abiotic stresses. This study is, therefore, focused on identification and characterization of sRNA biogenesis proteins in three important legume crops, namely chickpea, pigeonpea, and groundnut. Phylogenetic analysis of these proteins between legume species classified them into distinct clades and suggests the evolutionary conservation of these genes across the members of Papillionidoids subfamily. Variable expression of sRNA biogenesis genes in response to the biotic stresses among the three legumes indicate the possible existence of specialized regulatory mechanisms in different legumes. This is the first ever study to understand the role of sRNA biogenesis genes in response to pathogen attacks in the studied legumes.

Overexpression of SbAP37 in rice alleviates concurrent imposition of combination stresses and modulates different sets of leaf protein profiles.

KEY MESSAGE: SbAP37 transcription factor contributes to a combination of abiotic stresses when applied simultaneously in rice. It modulates a plethora of proteins that might regulate the downstream pathways to impart salt stress tolerance. APETALA type of transcription factor was isolated from Sorghum bicolor (SbAP37), overexpressed in rice using a salt inducible abscisic acid 2 (ABA2) promoter through Agrobacterium tumefaciens following in planta method. Transgenics were confirmed by PCR amplification of SbAP37, hygromycin phosphotransferase (hptII) marker and ABA2 promoter and DNA blot analysis. Plants were exposed to 150 mM NaCl coupled with high day/night 36 ± 2/25 ± 2 °C temperatures and also drought stress by withholding water for 1-week separately at the booting stage. SbAP37 expression was 2.8- to 4.7-folds higher in transgenic leaf under salt, but 1.8- to 3.3-folds higher in roots under drought stress. Native gene expression analysis showed that it is expressed more in stem than in roots and leaves under 150 mM NaCl and 6% PEG stress. In the present study, proteomic analysis of transgenics exposed to 150 mM NaCl coupled with elevated temperatures was taken up using quadrupole time-of-flight (Q-TOF) mass spectrometry (MS). The leaf proteome revealed 11 down regulated, 26 upregulated, 101 common (shared), 193 newly synthesized proteins in transgenics besides 368 proteins in untransformed plants. Some of these protein sets appeared different and unique to combined stresses. Our results suggest that the SbAP37 has the potential to improve combined stress tolerance without causing undesirable phenotypic characters when used under the influence of ABA2 promoter.

Toxicity and tolerance of aluminum in plants: tailoring plants to suit to acid soils.

Aluminum (Al) stress is one of the serious limiting factors in plant productivity in acidic soils, which constitute about 50 % of the world's potentially arable lands and causes anywhere between 25 and 80 % of yield losses depending upon the species. The mechanism of Al toxicity and tolerance has been examined in plants, which is vital for crop improvement and enhanced food production in the future. Two mechanisms that facilitate Al tolerance in plants are Al exclusion from the roots and the ability to tolerate Al in the symplast or both. Although efforts have been made to unravel Al-resistant factors, many aspects remain unclear. Certain gene families such as MATE, ALMT, ASR, and ABC transporters have been implicated in some plants for resistance to Al which would enhance the opportunities for creating crop plants suitable to grow in acidic soils. Though QTLs have been identified related to Al-tolerance, no crop plant that is tolerant to Al has been evolved so far using breeding or molecular approaches. The remarkable changes that plants experience at the physiological, biochemical and molecular level under Al stress, the vast array of genes involved in Al toxicity-tolerance, the underlying signaling events and the holistic image of the molecular regulation, and the possibility of creating transgenics for Al tolerance are discussed in this review.

Novel Etoposide Analogue Modulates Expression of Angiogenesis Associated microRNAs and Regulates Cell Proliferation by Targeting STAT3 in Breast Cancer.

Tumor microenvironment play role in angiogenesis and carcinogenesis. Etoposide, a known topoisomerase II inhibitor induces DNA damage resulting in cell cycle arrest. We developed a novel Etoposide analogue, Quinazolino-4ß-amidopodophyllotoxin (C-10) that show better efficacy in regulating cell proliferation and angiogenesis. We evaluated its role on expression of microRNAs-15, 16, 17 and 221 and its targets Bcl-2, STAT3 and VEGF that dictate cell proliferation and angiogenesis. Docking studies clearly demonstrated the binding of Etoposide and C-10 to STAT3. We conclude that combination of Etoposide or C-10 with miR-15, 16, 17 and 221 as a new approach to induce apoptosis and control angiogenesis in breast cancer.

Proline over-accumulation alleviates salt stress and protects photosynthetic and antioxidant enzyme activities in transgenic sorghum [Sorghum bicolor (L.) Moench].

Shoot-tip derived callus cultures of Sorghum bicolor were transformed by Agrobacterium tumefaciens as well as by bombardment methods with the mutated pyrroline-5-carboxylate synthetase (P5CSF129A) gene encoding the key enzyme for proline biosynthesis from glutamate. The transgenics were selfed for three generations and T4 plants were examined for 100 mM NaCl stress tolerance in pot conditions. The effect of salt stress on chlorophyll and carotenoid contents, photosynthetic rate, stomatal conductance, internal carbon dioxide concentration, transpiration rates, intrinsic transpiration and water use efficiencies, proline content, MDA levels, and antioxidant enzyme activities were evaluated in 40-day-old transgenic lines and the results were compared with untransformed control plants. The results show that chlorophyll content declines by 65% in untransformed controls compared to 30-38% loss (significant at P < 0.05) in transgenics but not carotenoid levels. Photosynthetic rate (PSII activity) was reduced in untransformed controls almost completely, while it declined by 62-88% in different transgenic lines. Salinity induced ca 100% stomatal closure in untransformed plants, while stomatal conductance was decreased only by 64-81% in transgenics after 4 days. The intercellular CO2 decreased by ca 30% in individual transgenic lines. Malondialdehyde (MDA) content was lower in transgenics compared to untransformed controls. The activities of superoxide dismutase (SOD; EC 1.15.1.1), catalase (CAT; EC 1.11.1.6) and glutathione reductase (GR; EC1.8.1.7) were quantified in leaves exposed to 100 mM NaCl stress and found higher in transgenics. The results suggest that transgenic lines were able to cope better with salt stress than untransformed controls by protecting photosynthetic and antioxidant enzyme activities.

Osmotin: a plant sentinel and a possible agonist of mammalian adiponectin.

Osmotin is a stress responsive antifungal protein belonging to the pathogenesis-related (PR)-5 family that confers tolerance to both biotic and abiotic stresses in plants. Protective efforts of osmotin in plants range from high temperature to cold and salt to drought. It lyses the plasma membrane of the pathogens. It is widely distributed in fruits and vegetables. It is a differentially expressed and developmentally regulated protein that protects the cells from osmotic stress and invading pathogens as well, by structural or metabolic alterations. During stress conditions, osmotin helps in the accumulation of the osmolyte proline, which quenches reactive oxygen species and free radicals. Osmotin expression results in the accumulation of storage reserves and increases the shelf-life of fruits. It binds to a seven-transmembrane-domain receptor-like protein and induces programmed cell death in Saccharomyces cerevisiae through RAS2/cAMP signaling pathway. Adiponectin, produced in adipose tissues of mammals, is an insulin-sensitizing hormone. Strangely, osmotin acts like the mammalian hormone adiponectin in various in vitro and in vivo models. Adiponectin and osmotin, the two receptor binding proteins do not share sequence similarity at the amino acid level, but interestingly they have a similar structural and functional properties. In experimental mice, adiponectin inhibits endothelial cell proliferation and migration, primary tumor growth, and reduces atherosclerosis. This retrospective work examines the vital role of osmotin in plant defense and as a potential targeted therapeutic drug for humans.

In vitro regeneration and ploidy level analysis of Eulophia ochreata Lindl.

Various parameters including explant-type, medium compositions, use of phytohormones and additives were optimized for direct and indirect regeneration of E. ochreata, a medicinal orchid under threat. Protocorm-like-bodies (PLBs) proved to be the best explants for shoot initiation, proliferation and callus induction. Murashige and Skoog's (MS) medium containing 2.5 mg L(-1) 6-benzylaminopurine (BAP), 1.0 mg L(-1) kinetin (Kin) and additives (adenine sulfate, arginine, citric acid, 30 mg L(-1) each and 50 mg L(-1) ascorbic acid) was optimal for shoot multiplication (12.1 shoots and 7.1 PLBs per explant with synchronized growth), which also produced callus. Shoot number was further increased with three successive subcultures on same media and approximately 40 shoots per explant were achieved after 3 cycles of 30 days each. Additives and casein hydrolysate (CH) showed advantageous effects on indirect shoot regeneration via protocorm-derived callus. Optimum indirect regeneration was achieved on MS containing additives, 500 mg L(-1) CH, 2.5 mg L(-1) BAP and 1.0 mg L(-1) Kin with 30 PLBs and 6 shoots per callus mass (approximately 5 mm size). The shoots were rooted (70% frequency) on one by fourth-MS medium containing 2.0 mg L(-1) indole-3-butyric acid, 200 mg L(-1) activated charcoal and additives. The rooted plantlets were hardened and transferred to greenhouse with 63% survival rate. Flow-cytometry based DNA content analysis revealed that the ploidy levels were maintained in in vitro regenerated plants. This is the first report for in vitro plant regeneration in E. ochreata.