High temperature and salt stress response in French bean (Phaseolus vulgaris)

Abiotic stresses, such as high temp., and salt stress are major factors which reduce crop productivity. Effects of high temp. (46-​48° C) and salt stress (0.4 M) on French bean (Phaseolus vulgaris)​, a major vegetable crop, were evaluated in terms of antioxidants and antioxidant enzymes in S-​9 cultivar. Both stresses caused similar responses in the plant. Oxidative stress indicators such as H2O2, TBARS, glutathione, ascorbic acid, and proline were significantly elevated. Similarly, antioxidant enzyme, guaiacol-​specific peroxidase (POX) was significantly elevated. Other enzymes, β-​amylase and acid phosphatase (AP) activities were marginally enhanced. However, stresses had contrasting effects on glutathione reductase (GR) and catalase (CAT)​, which were drastically reduced in temp. stress, and elevated in salt stress. No variations were obsd. in AP, POX, and CAT isoenzymes. Patterns of GR and β-​amylase isoenzymes differed between temp. and salt stress. SDS-​PAGE indicated entirely different sets of proteins in temp. and salt stressed seedlings. Growth rate and fresh mass were affected to same extent, relative to their resp. controls. DNA damage was more pronounced under temp. stress than under salt stress. Response mechanism of French bean appears to involve some players which are common to both the stresses, and few specific to individual stress

Effect of Cooking on Proteinase Inhibitors ofDolichos Lablab Bean (Dolichos Lablab perpureus L.)

Proteinase inhibitory activity in ten different varieties ofDolichos lablab perpureus. L. was determined. All the varieties tested exhibited appreciable level of proteinase inhibitory activity (PIA). The trypsin inhibitory activity (TIA) (Mean:20170 TIU/g) was relatively higher than the chymotrypsin inhibitory activity (CIA) (Mean: 15380 CIU/g). Effect of temperature and cooking on PIA was studied. The nature of cooking medium and duration of cooking had profound effect on the PIA. The dry fried seeds lost their PIA very rapidly (91% in 20 min). Seeds cooked in slightly alkaline medium lost their PIA quickly (89% in 30 min) compared to those cooked in acidic (80% in 30 min) and neutral pH (83% in 30 min). The PIA in green pods was also determined and they had only one third of the PIA (8200 TIU/g and 8125 CIU/g) found in the dry seeds

Identification of miRNAs from French bean (Phaseolus vulgaris) under low nitrate stress

Objective: In this study, we report the role of miRNAs involved under nitrogen starvation from widely grown vegetable crop, French bean. In recent years, a great deal of attention has been paid to the elucidation of miRNAs involved in low nitrate stress. Methods: To identify miRNAs expressed under stress, cDNA libraries were analyzed. Results: We reported the nine potential miRNAs with 67 targets involved in nutrient transporters and other stress specific genes. Among the miRNA sequences obtained 6 sequences belong to miR172 family, one with miR169. RT-PCR analysis of expression of miR172 family was induced upon low nitrate stress while miR169 family was repressed. In addition, Pvu-SN7b and Pvu-miR16 may be new members of miRNA172 and miR169 families, respectively. Conclusion: The targets of Pvu-SN7b were major protein kinases, one among which is the Protein Kinase CK2. CK2 Kinase is found to involve in transcription-directed signaling, gene control and cell-cycle regulation. Other targets of Pvu-SN7b were involved in DNA-dependent transcription regulation, photo-periodism, calcium-mediated signaling. Pvu-miR16 targets Thymidine kinase, the key enzyme of deoxy-nucleotide synthesis. The cleavage of these targets affects cell proliferation there by affecting nodule formation. Pvu-miR8 inhibits translation of its target protein Pre-protein translocase, a membrane-bound protein transporter involved in trans-membrane protein transportation. Together these results denote the response and role of miRNAs to nitrate-limiting conditions in French bean

Genome wide analysis of NAC transcription factors and their expression pattern during high temperature and drought stress in groundnut

NAC (NAM, ATAF1/2 and CUC2) is a prime plant specific transcription factor, which plays a pivotal role in stress signaling. Excavating a relatively large number of NAC TFs under complex environmental cues and understanding their molecular basis,\ua0remains a challenge. The objective of this study was to analyse a total of 76 NAC transcription factors of which 38 were from Arachis duranensis (AdNAC) and Arachis ipaensis (AiNAC) for phylogeny, chromosomal location, conserved motif identification including membrane bound NTLs (NAC trans-membrane like), promoter analysis and expression profiles under high temperature and drought stress.\ua0The study led to the identification of eight membrane bound NTLs, such as AdNAC26, AdNAC36, AiNAC16, AiNAC17, AiNAC37, AdNAC14, AiNAC12, and AiNAC29, and revealed that majority of NAC proteins had four NAC domain- containing conserved motifs and were localised at the nucleus. The study also reveals AdNAC21 and AiNAC3 as positive regulators under both stress conditions. Our results provide a basis for selection of promising stress- responsive NAC candidates for further functional analysis, leading to development of transgenics with improved productivity of groundnut varieties under drought and high temperature.NAC (NAM, ATAF1/2 et CUC2) est un facteur sp\ue9cifique primordial dans la transcription chez la plante, qui joue un r\uf4le principal dans la signalisation des stresses. Fouiller un nombre relativement important de NAC TFs sous le complexe des signaux environnementaux et comprendre leur base mol\ue9culaire, demeurent un d\ue9fi. L\u2019objectif de cette \ue9tude \ue9tait d\u2019analyser un total de 76 facteurs de transcription desquels 38 sont de Arachis duranensis (AdNAC) et Arachis ipaensis (AiNAC) pour la phylog\ue9nie, la localisation chromosomique, l\u2019identification du motif conserv\ue9 y comprises la membrane li\ue9e NTLs (semblable \ue0 NAC transe-membrane), analyse du promoteur et les profils d\u2019expression sous le stress de haute temp\ue9rature et de s\ue9cheresse. L\u2019\ue9tude a conduit \ue0 l\u2019identification de huit membranes NTLs li\ue9es, telles que AdNAC26, AdNAC36, AiNAC16, AiNAC17, AiNAC37, AdNAC14, AiNAC12, et AiNAC29, et a r\ue9v\ue9l\ue9 que la majorit\ue9 des prot\ue9ines NAC ont quatre domaines NAC- contenant des motifs conserv\ue9s et sont localis\ue9s dans le noyau. L\u2019\ue9tude a aussi r\ue9v\ue9l\ue9 AdNAC21 et AiNAC3 comme r\ue9gulateurs positifs sous les deux conditions \ue0 la fois. Nos r\ue9sultats ont fourni une base pour la s\ue9lection des NAC candidats donnant de r\ue9ponses satisfaisantes aux stresses pour une analyse fonctionnelle avanc\ue9e, conduisant au d\ue9veloppement des transg\ue9niques avec des vari\ue9t\ue9s d\u2019arachide \ue0 rendement am\ue9lior\ue9 sous la s\ue9cheresse et une haute temp\ue9rature

Expression of miRNAs confers enhanced tolerance to drought and salt stress in Finger millet (Eleusine coracona)

Plants respond to the environmental cues in various ways, recent knowledge of RNA interference in conferring stress tolerance had become a new hope of developing tolerant varieties. Here we attempt to unfold the molecular mechanism of stress tolerance through miRNA profiling and expression analysis in Finger millet (Eleusine coracona) under salt and drought stress conditions. The expression analysis of 12 stress specific conserved miRNAs was studied using semi-quantitative real time PCR and Northern blot assay. Our studies revealed that, although most of the miRNAs responded to the stresses, the expression of particular miRNA differed with the nature of stress and the tissue. The expression analysis was correlated with the existing data of their target genes. Abiotic stress up-regulated miRNAs are expected to target negative regulators of stress responses or positive regulators of processes that are inhibited by stresses. On the other hand, stress down-regulated miRNAs may repress the expression of positive regulators and/or stress up-regulated genes. Thus the current study of miRNAs and their targets under abiotic stress conditions displays miRNAs may be good candidates to attribute the stress tolerance in plants by transgenic technology

Biochemical response trends of Macrotyloma uniflorum, Lam. subjected to dehydration stress in different growth conditions

The mechanismof plant toleranceagainst dehydration is differs according to the growth status of the plant. To understand the similarities and differences in the drought responses of two different growth situations of horse gram, seedlings of normal plants along with regenerated tissue culture were subjected to dehydration stresshave been investigated. Enzymatic and non-enzymatic antioxidants of both seedlings behaved similar albeit minor variations. Activity of antioxidant enzymes of both seedlings compared to their controls showed a similar trend. Peroxidase (POX; EC 1.11.1.7), Superoxide dismutase (SOD; EC 1.15.1.1) and Glutathione reductase (GR; EC 1.6.4.2) were elevated. However, Catalase (CAT; EC 1.11.1.6) was reduced in both stressed seedlings. Also the antioxidants levels in both stressed plantlets exhibited 2 folds elevation of ascorbic acid and ~3 folds of GSH, but the elevation of proline was different where it was 6 folds in callus, while normal seedlings increased by 10 times compared to control. Stress markers hydrogen peroxide and thiobarbeturic acid reactive substances (TBARS) 2 folds increased, these coincides with higher levels of Peroxidase, reflecting a great damage of membrane in both stressed status. These suggest that horse gram seedlings behave in similar manner even if grown in different conditions and circumstances which confirm their similar biochemical resistance mechanism when exposed to water deficiency stress. © IDOSI Publications, 2013

Purification and characterization of a proteinase inhibitor from field bean, Dolichos lablab perpureus L.

A proteinase inhibitor resembling Bowman-Birk family inhibitors has been purified from the seeds of cultivar HA-3 of Dolichos lablab perpureus L. The protein was apparently homogeneous as judged by SDS-PAGE, PAGE, IEF, and immunodiffusion. The inhibitor had 12 mole 1/2-cystine and a few aromatic amino acids, and lacks tryptophan. Field bean proteinase inhibitor (FBPI) exhibited a pI of 4.3 and an M(r) of 18,500 Da. CD spectral studies showed random coiled secondary structure. Conformational changes were detected in the FBPI-trypsin/chymotrypsin complexes by difference spectral studies. Apparent K(a) values of complexes of inhibitor with trypsin and chymotrypsin were 2.1 x 107 M-1 and 3.1 x 107 M-1, respectively. The binary and ternary complexes of FBPI with trypsin and chymotrypsin have been isolated indicating 1:1 stoichiometry with independent sites for cognate enzymes. Amino acid modification studies showed lysine and tyrosine at the reactive sites of FBPI for trypsin and chymotrypsin, respectively

Quantitative Analysis of Polyamines in Paspalum scrobiculatum under Drought and Salt Stress

Abiotic stresses are the leading cause of crop loss worldwide. Polyamine (PAs) levels are known to change in response to abiotic stresses. Levels of PAs were monitored after inducing drought stress in 9 days old seedlings by withholding water over 12 days, and inducing salt stress by treating with 150–450 mM NaCl over 72 h in half strength Hoagland medium. Quantitation of PAs in root/shoot tissues by Reverse phase HPLC indicated that Spd is the major polyamine metabolite in Paspalum scrobiculatum and greater elevation in Spd was noted in salt stressed seedlings in concentration and time dependent manner. Drought stress in Paspalum scrobiculatum caused steady increase in PAs, PUT, Spd, Spm, and Tspm up to 12 days. Compared to drought stressed seedlings, salt stressed shoot exhibited higher amounts of all the PAs, including Tspm. These results suggested efficient adaptation of the plant to gradual dehydration induced by drought, also, considerable ability to withstand rapid dehydration induced by NaCl up to 300 mM over 3 days by increased production of PAs

Antioxidant and other biochemical defense responses of macrotyloma uniflorum (Lam.) Verdc. (Horse gram) induced by high temperature and salt stress

High temperature and salinity are the major ecological factors challenging crop productivity in the arid and semiarid regions of the world. Effects of high temperature (43-45°C) and salt stress (0.6 M) on Macrotyloma uniflorum (Lam.) Verdc. (Horse gram), were evaluated in terms of antioxidants and antioxidant enzymes. Both treatments caused typical stress responses in this tropical leguminosae. Oxidative stress indicators such as H 2O 2, TBARS, and proline were significantly elevated. Similarly, the antioxidant enzymes superoxide dismutase (SOD; EC 1.15.1.1), guaiacol peroxidase (POX; EC 1.11.1.7) and acid phosphates (AP; EC 3.1.3.2) were significantly elevated while catalase (CAT; EC 1.11.1.6) was reduced. These treatments had contrasting effects on glutathione reductase (GR; EC1.6.4.2) and b-amylase (EC 3.2.1.1). While temperature stress caused increase in GR and decrease in b-amylase, salt stress caused a counter effect. Contrast was also observed in ascorbate and glutathione which increased in temperature stress and reduced in salt stress. SDS-PAGE analysis indicated entirely different protein profiles in temperature and salt stressed seedlings. Growth rate and fresh mass were affected to same extent, relative to their controls. Taken together these data describes the similarities and peculiarities of key biochemical responses of Horse gram to high temperatures and salinity

Quantitative Analysis of Polyamines in Paspalum scrobiculatum under Drought and Salt Stress

Abiotic stresses are the leading cause of crop loss worldwide. Polyamine (PAs) levels are known to change in response to abiotic stresses. Levels of PAs were monitored after inducing drought stress in 9 days old seedlings by withholding water over 12 days, and inducing salt stress by treating with 150–450 mM NaCl over 72 h in half strength Hoagland medium. Quantitation of PAs in root/shoot tissues by Reverse phase HPLC indicated that Spd is the major polyamine metabolite in Paspalum scrobiculatum and greater elevation in Spd was noted in salt stressed seedlings in concentration and time dependent manner. Drought stress in Paspalum scrobiculatum caused steady increase in PAs, PUT, Spd, Spm, and Tspm up to 12 days. Compared to drought stressed seedlings, salt stressed shoot exhibited higher amounts of all the PAs, including Tspm. These results suggested efficient adaptation of the plant to gradual dehydration induced by drought, also, considerable ability to withstand rapid dehydration induced by NaCl up to 300 mM over 3 days by increased production of PAs