Kinetics of Adaptation to Osmotic Stress in Lentil (Lens culinaris Med.) Roots

When intact roots of lentil (Lens culinaris Med.) are subjected to severe osmotic stress by treatment with a solution of low water potential, they immediately begin to shrink. Within 10 to 15 minutes, shrinkage ceases, and within 20 minutes, the roots resume growth. The time lag between application of osmoticum and resumption of growth varies from about 10 to 30 minutes over the range of external water potentials of −2 to −12.4 bars. For external water potentials as low as −8.7 bars the new steady rate of growth in the presence of osmoticum is approximately equal to that prevailing before application of osmoticum. For external water potentials between −8.7 and −13 bars growth resumes, but the new rate is less than that prior to addition of osmoticum. Measurements of changes in the internal solute content during adaptation show that the solute content of the root increases but that the magnitude of the increase is, by itself, insufficient to account for the resumption of rapid growth.     

Genetic Analysis of Indian Lentil (Lens culinaris Medikus) Cultivars and Landraces Using RAPD and STMS Markers

Molecular analysis of 29 lentil (Lens culinaris) cultivars and landraces of Indian origin was carried out using twenty RAPD and ten cross-species STMS primers. A total of 97 markers (72 RAPD and 25 STMS) were amplified of which 42.3% were polymorphic. Genetic similarity among the cultivars and landraces was 89.7%. The observed results indicated low level of genetic diversity in the studied material. UPGMA cluster analysis for the combined data of RAPD and STMS revealed two broad clusters — Cluster I with three landraces and Cluster II containing all remaining landraces and cultivars except Precoz. Germplasm line Precoz was found to be the most distinct in individual as well as combined analyses. All cultivars and landraces except K-75 and L4076 could be discriminated from one another using combined data for the two techniques. Germplasm lines Precoz, L830 and cultivars L4147 and JL3 were quite distinct and could be potential germplasm resource.     

Genotype-specific responses to the effects of commercial Trichoderma formulations in lentil (Lens culinaris ssp. culinaris) in the presence and absence of the oomycete pathogen Aphanomyces euteiches

Members of the endophytic fungal genus Trichoderma have been established as plant-beneficial microbes and are most successful commercial biologicals in the form of bio-fertilisers, biocontrol agents, and growth stimulators. We report the variable interactions among different lentil genotypes and Trichoderma strains in both the presence and absence of biotic stress (root-rot pathogen Aphanomyces euteiches). Two commercial Trichoderma formulations, namely RootShield^® (RS) and RootShield^® Plus (RSP) based on T. harzianum T22 and T. virens G41, respectively, were evaluated for control of Aphanomyces root rot and plant growth promotion in 23 wild and cultivated lentil genotypes. No significant disease control was recorded with either formulation in any lentil genotype. Significant genotype-specific plant growth promotion was observed in terms of root and shoot development and leaf parameters in a genotype-specific manner. Genotypes of Lens culinaris and Lens tomentosus, both in the primary lentil gene pool, demonstrated the maximum response. The overall effect of Trichoderma treatment was markedly higher under biotically stressed conditions in comparison to unstressed conditions. In many cases, negative responses were recorded, particularly in the absence of root-rot disease. L. tomentosus PI 572390 exhibited positive responses for most of the tested parameters. Our findings clearly indicate that, in the case of lentil, plant genotype plays a major role in interactions among the tested Trichoderma strains and the plant. Moreover, the influence of Trichoderma was greater and more favourable under conditions of biotic stress vs. the absence of stress.     

Plectosporium tabacinum Root Rot Disease of White Lupine (Lupinus termis Forsk.) and its Biological Control by Streptomyces Species

Plectosporium tabacinum root rot disease of white lupine is reported for the first time in Cairo Governorate provinces. Symptoms of the disease appeared on young seedlings as stunting, yellowing and wilting of the foliage. Rotted roots were first became light brown and the lesions progressively extended over the whole root system and became dark brown. Plants died when the whole root system had become infected. For successful biological control of the disease 70 rhizosphere actinomycetes were isolated by the use of normal standard isolation techniques. Three of these isolates were found to be strongly antagonistic against P. tabacinum in vitro . They also significantly reduced the incidence of white lupine root rot disease in soil infested with P. tabacinum in greenhouse trials. The three actinomycete isolates were identified as Streptomyces cyanoviridis , Streptomyces murinus and Streptomyces griseoplanus .     

Expression in Escherichia coli of Three Different Soybean Late Embryogenesis Abundant (LEA) Genes to Investigate Enhanced Stress Tolerance

In order to identify the function of late embryogenesis abundant (LEA) genes, in vitro functional analyses were perfo rmed using an Escherichia coli heterologous expression system. Three soybean late embryogenesis abundant (LEA) genes, PM11 (GenBank accession No. AF004805; group 1), PM30 (AF1 17884; group 3), and ZLDE-2 (AY351918; group 2), were cloned and expressed in a pET-28a system.The gene products were separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and identified by mass spectrometry. E. coli cells containing the recombinant plasmids or empty vector as controls were treated by salt and low temperature stress. Compared with control cells, the E. coli cells expressing either PM11 or PM30 showed a shorter lag period and improved growth when transferred to LB (Luria-Bertani) liquid media containing 800 mmol/L NaCl or 700 mmol/L KCl or after 4 ℃ treatment. E. coli cells expressing ZLDE-2 did not show obvious growth improvement both in either high KCl medium or after 4 ℃ treatment. The results indicate that the E. coli expression system is a simple, useful method to identify the functions of some stress-tolerant genes from plants.     

Expression in Escherichia coli of Three Different Soybean Late Embryogenesis Abundant （LEA） Genes to Investigate Enhanced Stress Tolerance

In order to identify the function of late embryogenesis abundant (LEA) genes, in vitro functional analyses were performed using an Escherichia coli heterologous expression system. Three soybean late embryogenesis abundant (LEA) genes, PMll (GenBank accession No. AF004805; group 1), PM30(AF117884; group 3), and ZLDE-2 (AY351918; group 2), were cloned and expressed in a pET-28a system.The gene products were separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and identified by mass spectrometry. E. coli cells containing the recombinant plasmids or empty vector as controls were treated by salt and low temperature stress. Compared with control cells, the E. coli cells expressing either PMll or PM30 showed a shorter lag period and improved growth when transferred to LB (Luria-Bertani) liquid media containing 800 mmol/L NaC1 or 700 mmol/L KC1 or after 4℃ treatment. E. coli cells expressing ZLDE-2 did not show obvious growth improvement both in either high KC1 medium or after 4℃ treatment. The results indicate that the E. coli expression system is a simple, useful method to identify the functions of some stress-tolerant genes from plants.     

不同基因型新城疫病毒HN基因保守区域的克隆表达及免疫活性的比较

对于NDV不同基因型毒株的HN基因的氨基酸序列比较后发现,基因Ⅶ型的毒株在第65~75位的氨基酸序列较为保守,而其他各基因型在该区域则不尽相同。因此本文克隆了NDV基因Ⅱ、Ⅶ、Ⅸ型的代表毒株La Sota、GX-2、F48E9的含有该区域的序列,并进行蛋白表达,通过特异性抗血清对表达肽段进行抗原性测定。应用表达的蛋白免疫SPF鸡,用ELISA检测各组的抗体水平。结果表明3个毒株在反应原性上存在差异。应用NDV F48E9强毒株攻毒,结果显示各多肽蛋白的保护率不同,表明在该区域这3个毒株之间存在着免疫原性差异。     

Evaluation and Validation of Housekeeping Genes as Reference for Gene Expression Studies in Pigeonpea (Cajanus cajan) Under Drought Stress Conditions

Gene expression analysis using quantitative real-time PCR (qRT-PCR) is a very sensitive technique and its sensitivity depends on the stable performance of reference gene(s) used in the study. A number of housekeeping genes have been used in various expression studies in many crops however, their expression were found to be inconsistent under different stress conditions. As a result, species specific housekeeping genes have been recommended for different expression studies in several crop species. However, such specific housekeeping genes have not been reported in the case of pigeonpea (Cajanus cajan) despite the fact that genome sequence has become available for the crop. To identify the stable housekeeping genes in pigeonpea for expression analysis under drought stress conditions, the relative expression variations of 10 commonly used housekeeping genes (EF1α, UBQ10, GAPDH, 18SrRNA, 25SrRNA, TUB6, ACT1, IF4α, UBC and HSP90) were studied on root, stem and leaves tissues of Asha (ICPL 87119). Three statistical algorithms geNorm, NormFinder and BestKeeper were used to define the stability of candidate genes. geNorm analysis identified IF4α and TUB6 as the most stable housekeeping genes however, NormFinder analysis determined IF4α and HSP90 as the most stable housekeeping genes under drought stress conditions. Subsequently validation of the identified candidate genes was undertaken in qRT-PCR based gene expression analysis of uspA gene which plays an important role for drought stress conditions in pigeonpea. The relative quantification of the uspA gene varied according to the internal controls (stable and least stable genes), thus highlighting the importance of the choice of as well as validation of internal controls in such experiments. The identified stable and validated housekeeping genes will facilitate gene expression studies in pigeonpea especially under drought stress conditions.     

Root Morphology and Gene Expression Analysis in Response to Drought Stress in Maize (Zea mays)

Water-deficit stress tolerance is a complex trait, and water deficit results in various physiological and chemical changes in maize (Zea mays L.) and exacerbates pre-harvest aflatoxin contamination. The objective of this study was to characterize the variations in morphology, physiology, and gene expression in two contrasting inbred lines, Lo964 and Lo1016, in order to understand the differences in response to water-deficit stress. The results revealed that Lo964 was less sensitive to water-deficit stress, and had a strong lateral root system and a higher root/shoot ratio in comparison to Lo1016. In response to water-deficit stress by comparing stressed versus well-watered conditions, abscisic acid syntheses were increased in leaves, roots, and kernels of both Lo964 and Lo1016, but by different magnitudes. Indole-3-acetic acid (IAA) was undetectable in the leaves and roots of either genotype regardless of treatments, but increases of 58% and 8% in IAA concentration were observed in 20 DAP kernels, in response to water-deficit stress, respectively. The expression of the MIPS was up-regulated 7-fold in leaf tissues of Lo964 compared to Lo1016 at watered conditions, but decreased significantly to similar levels in both genotypes at water-deficit conditions. ZmPR10 and ZmFer1 expressions tended to up-regulate although ZmPR10 was expressed higher in root tissue while ZmFer1 was expressed higher in leaf tissue. Further study is needed to confirm if Lo964 has reduced aflatoxin contamination associated with the drought tolerance in the field in order to utilize the resistant trait in breeding.     

Studies on interaction of Meloidogyne incognita (Kofoid and White) Chitwood and Fusarium solani (Mart.) Sacc forming a disease complex in lentil (Lens culinaris Medik.)

Abstract

An experiment was conducted to study the effects of interaction between Meloidogyne incognita and Fusarium solani on plant length, fresh and dry weights, number of pods, chlorophyll, carotenoid, nitrogen and phosphorus contents and nitrate reductase activity in lentil plants. The results reveal a maximum damage occurring in all the plant growth, biochemical and nutrient parameters, in plants inoculated with M. incognita 10 days prior to F. solani (Mi?→?Fs). This was followed by simultaneous (Mi?+?Fs) inoculations, fungus inoculation 10 days prior to nematode (Fs?→?Mi), M. incognita alone and F. solani alone treatments. Nematode reproduction factor and root galling were highest in individual inoculation of M. incognita, while root rotting percentage was highest when nematode was inoculated 10 days prior to fungus followed by simultaneous inoculation with both nematode and fungus.     

Measuring Genes Expression Involved in Enzymatic Defense and ABA Biosynthesis in Solanum lycopersicum L. (Red Cloud Cultivar) under Cold Stress

Russian Journal of Plant Physiology - ‘Red Cloud’ (RC) is a cultivar of tomato (Solanum lycopersicum L.) which one of the main agricultural products classified as cultivated plants, it...     

Inhibitory properties and solution structure of a potent Bowman-Birk protease inhibitor from lentil (Lens culinaris, L) seeds

Bowman-Birk serine protease inhibitors are a family of small plant proteins, whose physiological role has not been ascertained as yet, while chemopreventive anticarcinogenic properties have repeatedly been claimed. In this work we present data on the isolation of a lentil (Lens culinaris, L., var. Macrosperma) seed trypsin inhibitor (LCTI) and its functional and structural characterization. LCTI is a 7448 Da double-headed trypsin/chymotrypsin inhibitor with dissociation constants equal to 0.54 nM and 7.25 nM for the two proteases, respectively. The inhibitor is, however, hydrolysed by trypsin in a few minutes timescale, leading to a dramatic loss of its affinity for the enzyme. This is due to a substantial difference in the kon and k*on values (1.1 microM-1.s-1 vs. 0.002 microM-1.s-1), respectively, for the intact and modified inhibitor. A similar behaviour was not observed with chymotrypsin. The twenty best NMR structures concurrently showed a canonical Bowman-Birk inhibitor (BBI) conformation with two antipodal beta-hairpins containing the inhibitory domains. The tertiary structure is stabilized by ion pairs and hydrogen bonds involving the side chain and backbone of Asp10-Asp26-Arg28 and Asp36-Asp52 residues. At physiological pH, the final structure results in an asymmetric distribution of opposite charges with a negative electrostatic potential, centred on the C-terminus, and a highly positive potential, surrounding the antitryptic domain. The segment 53-55 lacks the anchoring capacity found in analogous BBIs, thus rendering the protein susceptible to hydrolysis. The inhibitory properties of LCTI, related to the simultaneous presence of two key amino acids (Gln18 and His54), render the molecule unusual within the natural Bowman-Birk inhibitor family.     

Identification of Reference Genes for Quantitative Real-Time PCR in Date Palm (Phoenix dactylifera L.) Subjected to Drought and Salinity

Date palm is an important crop plant in the arid and semi-arid regions supporting human population in the Middle East and North Africa. These areas have been largely affected by drought and salinity due to insufficient rainfall and improper irrigation practices. Date palm is a relatively salt- and drought-tolerant plant and more recently efforts have been directed to identifying genes and pathways that confer stress tolerance in this species. Quantitative real-time PCR (qPCR) is a promising technique for the analysis of stress-induced differential gene expression, which involves the use of stable reference genes for normalizing gene expression. In an attempt to find the best reference genes for date palm’s drought and salinity research, we evaluated the stability of 12 most commonly used reference genes using the geNorm, NormFinder, BestKeeper statistical algorithms and the comparative ΔC_T method. The comprehensive results revealed that HEAT SHOCK PROTEIN (HSP), UBIQUITIN (UBQ) and YTH domain-containing family protein (YT521) were stable in drought-stressed leaves whereas GLYCERALDEHYDE-3-PHOSPHATE DEHYDROGENASE (GAPDH), ACTIN and TUBULIN were stable in drought-stressed roots. On the other hand, SMALL SUBUNIT RIBOSOMAL RNA (25S), YT521 and 18S ribosomal RNA (18S); and UBQ, ACTIN and ELONGATION FACTOR 1-ALPHA (eEF1a) were stable in leaves and roots, respectively, under salt stress. The stability of these reference genes was verified by using the abiotic stress-responsive CYTOSOLIC Cu/Zn SUPEROXIDE DISMUTASE (Cyt-Cu/Zn SOD), an ABA RECEPTOR, and a PROLINE TRANSPORTER 2 (PRO) genes. A combination of top 2 or 3 stable reference genes were found to be suitable for normalization of the target gene expression and will facilitate gene expression analysis studies aimed at identifying functional genes associated with drought and salinity tolerance in date palm.     

GABA accumulation and oxidative damage responses to salt,osmotic and H2O2 treatments in two lentil (Lens culinaris Medik) accessions

Abiotic stresses such as cold, drought, heat, salinity, nutrient deficiency, and toxicity adversely affect lentil yields worldwide. Therefore, the purpose of this study was to investigate the response of two lentil cultivars (Lens culinaris Medik) (Jordan 1 and Jordan 2) to NaCl, mannitol, sorbitol, and H₂O₂ via the characterization of seed germination, accumulation of reactive oxygen species, and γ-aminobutyric acid (GABA) level. There was a significant increase in GABA and malondialdehyde (MDA) levels in the two lentil cultivars under all treatments. Jordan 1 showed the highest germination percentages with p-values: 0.009, 0.013, 0.026, and 0.015, while Jordan 2 seedlings showed the highest GABA levels with p-values: 0.023, 0.007, 0.023, and 0.019 and MDA accumulation with p-values: 0.009, 0.012, 0.007, and 0.009 under salt, osmotic, and oxidative stresses, respectively, compared with Jordan 1 seedlings under the same treatments. Our results indicate that GABA shunt is a key signaling and metabolic pathway that allows adaptation of lentil seedlings to salt, osmotic, and oxidative stresses. In addition, Jordan 1 cultivar showed significant tolerance to abiotic stress treatments and it is the most recommended lentil cultivar to be used in soil with high salt and osmotic contents.     

Molecular Cloning and Adversity Stress Expression Analysis of SPDS Genes in Mulberry (Morus notabilis)

Russian Journal of Plant Physiology - Spermidine (SPD), as a signal molecule, participates in the response of plants to adversity stress. In the biosynthesis of SPD, spermidine synthase (SPDS) is...