Morpho-physiological adaptations to weed competition impair green bean (Phaseolus vulgaris) ability to overcome moderate salt stress.

The two stresses of weed competition and salt salinity lead to crop yield losses and decline in the productivity of agricultural land. These constraints threaten the future of food production because weeds are more salt stress tolerant than most crops. Climate change will lead to an increase of soil salinity worldwide, and possibly exacerbate the competition between weeds and crops. This aspect has been scarcely investigated in the context of weed-crop competition. Therefore, we conducted a field experiment on green beans (Phaseolus vulgaris ) to investigate the combined impact of weed competition and salt stress on key morpho-physiological traits, and crop yield. We demonstrated that soil salinity shifted weed composition toward salt tolerant weed species (Portulaca oleracea and Cynodon dactylon ), while it reduced the presence of lower tolerance species. Weed competition activated adaptation responses in green bean such as reduced leaf mass per area and biomass allocation to the stem, unchanged stomatal density and instantaneous water use efficiency, which diverge from those that are typically observed as a consequence of salt stress. The morpho-physiological modifications caused by weeds is attributed to the alterations of light intensity and/or quality, further confirming the pivotal role of the light in crop response to weeds. We concluded that higher yield loss caused by combined salt stress and weed competition is due to impaired morpho-physiological responses, which highlights the negative interaction between salt stress and weed competition. This phenomenon will likely be more frequent in the future, and potentially reduce the efficacy of current weed control methods.

Deciphering the impact of cold-adapted bioinoculants on rhizosphere dynamics, biofortification, and yield of kidney bean across varied altitudinal zones.

Agriculture stands as a thriving enterprise in India, serving as both the bedrock of economy and vital source of nutrition. In response to the escalating demands for high-quality food for swiftly expanding population, agricultural endeavors are extending their reach into the elevated terrains of the Himalayas, tapping into abundant resources for bolstering food production. Nonetheless, these Himalayan agro-ecosystems encounter persistent challenges, leading to crop losses. These challenges stem from a combination of factors including prevailing frigid temperatures, suboptimal farming practices, unpredictable climatic shifts, subdivided land ownership, and limited resources. While the utilization of chemical fertilizers has been embraced to enhance the quality of food output, genuine concerns have arisen due to the potential hazards they pose. Consequently, the present investigation was initiated with the objective of formulating environmentally friendly and cold-tolerant broad ranged bioinoculants tailored to enhance the production of Kidney bean while concurrently enriching its nutrient content across entire hilly regions. The outcomes of this study unveiled noteworthy advancements in kidney bean yield, registering a substantial increase ranging from 12.51 ± 2.39 % to 14.15 ± 0.83 % in regions of lower elevation (Jeolikote) and an even more remarkable surge ranging from 20.60 ± 3.03 % to 29.97 ± 5.02 % in higher elevated areas (Chakrata) compared to the control group. Furthermore, these cold-tolerant bioinoculants exhibited a dual advantage by fostering the enhancement of essential nutrients within the grains and fostering a positive influence on the diversity and abundance of microbial life in the rhizosphere. As a result, to effectively tackle the issues associated with chemical fertilizers and to achieve sustainable improvements in both the yield and nutrient composition of kidney bean across varying elevations, the adoption of cold-tolerant Enterobacter hormaechei CHM16, and Pantoea agglomerans HRM 23, including the consortium, presents a promising avenue. Additionally, this study has contributed significant insights-into the role of organic acids like oxalic acid in the solubilization of nutrients, thereby expanding the existing knowledge in this specialized field.

The impact of nanofertilizer on agro-morphological criteria, yield, and genomic stability of common bean (Phaseolus vulgaris L.).

The use of agricultural fertilizers is one of the methods to beat the desired enormous increase in universal food production. The application of nanotechnology in agriculture is regarded as one of the promising approaches to elevate crop production. Whereas mineral nutrients play a crucial role in the growth and yield of the common bean. The experiments were conducted to investigate the application effect of micronutrients as nanoparticles (MN-NPs) on the common ben plants. The trial was performed in the field in El-Menofya, Egypt, through two seasons (2019 & 2020) in a randomized complete block design with three replicates and four combinations of MN-NPs (ZnO, MnO2 and MoO3) with concentrations 0, 10, 20, 30, 40 mg/L as a foliar application. The data exhibited that the foliar application of MN-NPs significantly upgraded the vegetative growth characters, flower number/plant, photosynthetic pigments, and yield. The concentration of 40 mg/L of MN-NPs leads to improving the vegetative growth, flowering number, and yield characteristics of the common bean. While the biochemical components varied in their response to MN-NPs combinations. The recommended MN-NPs concentration to ameliorate the common bean growth and yield was 40 mg/L.

Evaluation of water stress and co-inoculation of Azospirillum brasilense and Rhizobium tropici in beans (Phaseolus vulgaris l) / Avaliação do estratégio de água e co-inoculação de Azospirillum brasilense e Rhizobium tropici in beans (Phaseolus vulgaris l) / Evaluación del estrés hídrico y la coinoculación de Azospirillum brasilense y Rhizobium tropici en frijoles (Phaseolus vulgaris l)

Climate change has caused major changes in abiotic factors, with water stress as the greatest threat to agricultural production. The measures aimed at alleviating the problems caused by this limiting production factor have occurred through the adoption of sustainable strategies, especially microbial biotechnology, which uses the interactions between the microorganism and the plant, ensuring productive quality and inducing plant resistance to stresses biotic and abiotic. The objective of the present work was to evaluate the biological nitrogen fixation and the development of bean seedlings, with co-inoculation of two types of inoculants, which were subjected to water stress by different pot capacities. The experiment was conducted in a greenhouse, at Universidade Paranaense - UNIPAR, from April to June 2019. The experimental design was completely randomized (DIC), with 5 replications, 16 treatments and 80 experimental units. The cultivar used was SCS Riqueza. The parameters evaluated were pot capacity (25%, 50%, 75% and 90%); small, large and total nodules, shoot and root length, dry and fresh weight, total carbon and nitrogen. The evaluation of the morphological parameters of the bean seedlings indicated that the co- inoculation technique promoted beneficial effects for the dry mass parameters of shoot, nodule and root. The analysis of the percentage of carbon and nitrogen in the tissues of the seedlings provided an increase in the concentration of these elements in treatments that involved co-inoculation (Azospirillum brasilensis and Rhizobium tropici) with pot capacities of 25 and 75% (CV), demonstrating that the association of microorganisms is beneficial in the limiting water situation.(AU)

A mudança climática tem causado grandes mudanças nos fatores abióticos, sendo o estresse hídrico a maior ameaça à produção agrícola. As medidas destinadas a aliviar os problemas causados por este fator limitante de produção ocorreram através da adoção de estratégias sustentáveis, especialmente a biotecnologia microbiana, que utiliza as interações entre o microorganismo e a planta, garantindo a qualidade produtiva e induzindo a resistência da planta ao estresse biótico e abiótico. O objetivo do presente trabalho foi avaliar a fixação biológica de nitrogênio e o desenvolvimento de mudas de feijão, com co-inoculação de dois tipos de inoculantes, que foram submetidos ao estresse hídrico por diferentes capacidades de vaso. A experiência foi realizada em uma estufa, na Universidade Paranaense - UNIPAR, de abril a junho de 2019. O projeto experimental foi completamente randomizado (DIC), com 5 réplicas, 16 tratamentos e 80 unidades experimentais. A cultivar utilizada foi a SCS Riqueza. Os parâmetros avaliados foram a capacidade do vaso (25%, 50%, 75% e 90%); nódulos pequenos, grandes e totais, comprimento do rebento e da raiz, peso seco e fresco, carbono total e nitrogênio. A avaliação dos parâmetros morfológicos das mudas de feijão indicou que a técnica de co-inoculação promoveu efeitos benéficos para os parâmetros de massa seca do turião, nódulo e raiz. A análise da porcentagem de carbono e nitrogênio nos tecidos das mudas proporcionou um aumento na concentração destes elementos nos tratamentos que envolveram a co-inoculação (Azospirillum brasilensis e Rhizobium tropici) com capacidades de vaso de 25 e 75% (CV), demonstrando que a associação de microorganismos é benéfica na situação limite da água.(AU)

El cambio climático ha provocado importantes cambios en los factores abióticos, siendo el estrés hídrico la mayor amenaza para la producción agrícola. Las medidas encaminadas a paliar los problemas causados por este factor limitante de la producción se han producido mediante la adopción de estrategias sostenibles, especialmente la biotecnología microbiana, que utiliza las interacciones entre el microorganismo y la planta, asegurando la calidad productiva e induciendo la resistencia de la planta a los estreses bióticos y abióticos. El objetivo del presente trabajo fue evaluar la fijación biológica de nitrógeno y el desarrollo de plántulas de frijol, con la co-inoculación de dos tipos de inoculantes, que fueron sometidos a estrés hídrico por diferentes capacidades de maceta. El experimento se realizó en un invernadero, en la Universidade Paranaense - UNIPAR, de abril a junio de 2019. El diseño experimental fue completamente al azar (DIC), con 5 repeticiones, 16 tratamientos y 80 unidades experimentales. El cultivar utilizado fue SCS Riqueza. Los parámetros evaluados fueron capacidad de maceta (25%, 50%, 75% y 90%); nódulos pequeños, grandes y totales, longitud de brotes y raíces, peso seco y fresco, carbono y nitrógeno total. La evaluación de los parámetros morfológicos de las plántulas de frijol indicó que la técnica de coinoculación promovió efectos beneficiosos para los parámetros de masa seca de brotes, nódulos y raíces. El análisis del porcentaje de carbono y nitrógeno en los tejidos de las plántulas proporcionó un aumento en la concentración de estos elementos en los tratamientos que involucraron la coinoculación (Azospirillum brasilensis y Rhizobium tropici) con capacidades de maceta de 25 y 75% (CV), demostrando que la asociación de microorganismos es beneficiosa en la situación de agua limitante.(AU)

Glyphosate at low doses changes the physiology and increases the productivity of common bean as affected by sowing seasons.

Glyphosate applied at low doses can stimulate photosynthesis and yield. The objective of this study was to evaluate the application of low doses of glyphosate and sowing seasons in physiological characteristics and grain yield of common bean of early cycle. Two experiments were conducted in the field, the first in winter season and the second in wet season. The experimental design was a randomized complete block design, consisting of five and seven low doses of glyphosate and one period of application, with four replications. Glyphosate low dose of 108.0 g a.e. ha-1 impaired net CO2 assimilation rate, stomatal conductance, transpiration rate, instantaneous carboxylation efficiency, number of pods per plant, number of grains per plant and number of grains per pod. Glyphosate dose of 7.2 g a.e. ha-1 provided a 23% increase in grain yield in winter season, and the dose of 36.0 g a.e. ha-1 provided a 109% increase in grain yield in wet season. To our knowledge, this is the first report on effect of glyphosate at low doses and sowing season to obtain yield increases in common bean of early cycle.

Effects of oxygen fertilization on damage reduction in flooded snap bean (Phaseolus vulgaris L.).

Flooding is one of the major abiotic stresses for vegetable production in Florida. Hydroponic and pot trials were conducted with snap bean to evaluate the effects of oxygen fertilization on the biochemical and physiological status of flooded snap bean plants. There were three treatments in the hydroponic trials were: (1) flooded (control), (2) bubble aeration with ambient air, and (3) hydrogen peroxide (H2O2) applied at the beginning of the trial. Plant health was evaluated by determining nitrogen (N) and phosphorus (P) uptake rates. The greenhouse pot trials were used to quantify the effects of three different application rates of solid oxygen fertilizers as calcium peroxide (CaO2) and magnesium peroxide (MgO2). The results showed that plant N and P uptake rates were significantly greater (p < 0.05) with H2O2 than without H2O2. The N uptake rates with H2O2 were like that of those with bubbling. The uptake rate of NH4+ was significantly greater than that of NO3- with the bubbling and H2O2 conditions, but the uptake rate of NO3- was significantly greater than that of NH4+ in the flooding condition. The plant height, leaf greenness, shoot biomass, and yield were all significantly greater with CaO2 or MgO2 than without either solid oxygen fertilizer. The minimum damage of flooded snap bean was found with 2 g CaO2 or 4 g MgO2 per pot. These results indicated that oxygen fertilization may potentially improve yield of flooded snap bean plants.

Transcriptomic analysis of Mesoamerican and Andean Phaseolus vulgaris accessions revealed mRNAs and lncRNAs associated with strain selectivity during symbiosis.

Legume plants establish a nitrogen-fixing symbiosis with soil bacteria known as rhizobia. Compatibility between legumes and rhizobia is determined at species-specific level, but variations in the outcome of the symbiotic process are also influenced by the capacity of the plant to discriminate and select specific strains that are better partners. We compared the transcriptional response of two genetically diverse accessions of Phaseolus vulgaris from Mesoamerica and South Andes to Rhizobium etli strains that exhibit variable degrees of symbiotic affinities. Our results indicate that the plant genotype is the major determinant of the transcriptional reprogramming occurring in roots at early stages of the symbiotic interaction. Differentially expressed genes (DEGs) regulated in the Mesoamerican and the Andean accessions in response to specific strains are different, but they belong to the same functional categories. The common and strain-specific transcriptional responses to rhizobia involve distinct transcription factors and cis-elements present in the promoters of DEGs in each accession, showing that diversification and domestication of common bean at different geographic regions influenced the evolution of symbiosis differently in each genetic pool. Quantitative PCR analysis validated our transcriptional datasets, which constitute a valuable source of coding and non-coding candidate genes to further unravel the molecular determinants governing the mechanisms by which plants select bacterial strains that produce a better symbiotic outcome.

Heat shock transcription factor (Hsf) gene family in common bean (Phaseolus vulgaris): genome-wide identification, phylogeny, evolutionary expansion and expression analyses at the sprout stage under abiotic stress.

BACKGROUND: Common bean (Phaseolus vulgaris) is an essential crop with high economic value. The growth of this plant is sensitive to environmental stress. Heat shock factor (Hsf) is a family of antiretroviral transcription factors that regulate plant defense system against biotic and abiotic stress. To date, few studies have identified and bio-analyzed Hsfs in common bean. RESULTS: In this study, 30 Hsf transcription factors (PvHsf1-30) were identified from the PFAM database. The PvHsf1-30 belonged to 14 subfamilies with similar motifs, gene structure and cis-acting elements. The Hsf members in Arabidopsis, rice (Oryza sativa), maize (Zea mays) and common bean were classified into 14 subfamilies. Collinearity analysis showed that PvHsfs played a role in the regulation of responses to abiotic stress. The expression of PvHsfs varied across different tissues. Moreover, quantitative real-time PCR (qRT-PCR) revealed that most PvHsfs were differentially expressed under cold, heat, salt and heavy metal stress, indicating that PvHsfs might play different functions depending on the type of abiotic stress. CONCLUSIONS: In this study, we identified 30 Hsf transcription factors and determined their location, motifs, gene structure, cis-elements, collinearity and expression patterns. It was found that PvHsfs regulates responses to abiotic stress in common bean. Thus, this study provides a basis for further analysis of the function of PvHsfs in the regulation of abiotic stress in common bean.

Bacterial type III effector-induced plant C8 volatiles elicit antibacterial immunity in heterospecific neighbouring plants via airborne signalling.

Upon sensing attack by pathogens and insect herbivores, plants release complex mixtures of volatile compounds. Here, we show that the infection of lima bean (Phaseolus lunatus L.) plants with the non-host bacterial pathogen Pseudomonas syringae pv. tomato led to the production of microbe-induced plant volatiles (MIPVs). Surprisingly, the bacterial type III secretion system, which injects effector proteins directly into the plant cytosol to subvert host functions, was found to prime both intra- and inter-specific defense responses in neighbouring wild tobacco (Nicotiana benthamiana) plants. Screening of each of 16 effectors using the Pseudomonas fluorescens effector-to-host analyser revealed that an effector, HopP1, was responsible for immune activation in receiver tobacco plants. Further study demonstrated that 1-octen-3-ol, 3-octanone and 3-octanol are novel MIPVs emitted by the lima bean plant in a HopP1-dependent manner. Exposure to synthetic 1-octen-3-ol activated immunity in tobacco plants against a virulent pathogen Pseudomonas syringae pv. tabaci. Our results show for the first time that a bacterial type III effector can trigger the emission of C8 plant volatiles that mediate defense priming via plant-plant interactions. These results provide novel insights into the role of airborne chemicals in bacterial pathogen-induced inter-specific plant-plant interactions.

Fe and Zn stress induced gene expression analysis unraveled mechanisms of mineral homeostasis in common bean (Phaseolus vulgaris L.).

Iron (Fe) and zinc (Zn) stress significantly affects fundamental metabolic and physiological processes in plants that results in reduction of plant growth and development. In the present study, common bean variety; Shalimar French Bean-1 (SFB-1) was used as an experimental material. Four different MGRL media i.e. normal MGRL medium (Control), media without Fe (0-Fe), media without Zn (0-Zn) and media with excess Zn (300-Zn) were used for growing seeds of SFB-1 under in vitro condition for three weeks under optimum conditions. Three week old shoot and root tissues were harvested from the plants grown in these four different in vitro conditions and were, subjected to Fe and Zn estimation. Further, extraction of total RNA for differential gene expression of ten candidate genes selected based on our in silico investigation and their classification, phylogeny and expression pattern was unraveled. Expression analysis of three candidate genes (OPT3, NRAMP2 and NRAMP3) in roots revealed possible cross talk among Fe/Zn stress that was further confirmed by observing less accumulation of Fe in roots under both these conditions. However, we observed, higher accumulation of Fe in shoots under 0-Fe condition compared to control that suggests precise sensing for priority based compartmentalization and partitioning leading to higher accumulation of Fe in shoots. Furthermore, the expression analysis of IRT1, FRO1 and Ferritin 1 genes under Fe/Zn stress suggested their role in uptake/transport and signaling of Fe and Zn, whereas the expression of ZIP2, NRAMP1, HA2 and GLP1 genes were highly responsive to Zn in Phaseolus vulgaris. The identified genes highly responsive to Fe and Zn stress condition can be potential candidates for overcoming mineral stress in dicot crop plants.

Do Common Beans (Phaseolus vulgaris L.) Promote Good Health in Humans? A Systematic Review and Meta-Analysis of Clinical and Randomized Controlled Trials.

The common bean is a nutrient-dense food empirically known to have beneficial effects on human health. Many studies have looked at the effects of "pulses" on different health issues, providing general overviews of the importance of each pulse in health studies. This study systematically reviews and provides meta-analyses of the effect of bean extract as a supplement or whole bean on four health issues (cardiovascular diseases, diabetes mellitus, obesity, and cancers) from a dissection of clinical and randomized controlled trials using human subjects. A digital search in PubMed and Google ScholarTM resulted in 340 articles, with only 23 peer-reviewed articles matching our inclusion criteria. Findings indicated that common beans reduced LDL cholesterol by 19 percent, risk of cardiovascular disease (CVD) by 11 percent, and coronary heart disease (CHD) by 22 percent. Besides this, we noted variances in the literature on cancer findings, with some authors stating it reduced the proliferation of some kinds of tumor cells and reduced the growth of polyps, while others did not specifically examine cancers but the predisposing factors alone. However, diabetes studies indicated that the postprandial glucose level at the peak of 60 min for common bean consumers was low (mean difference = -2.01; 95% CI [-4.6, -0.63]), but the difference between the treated and control was not significant, and there was a high level of heterogeneity among studies (I2 = 98%). Only obesity studies indicated a significantly high level of weight gain among control groups (mean difference = 1.62; 95% CI [0.37, 2.86]). There is a need for additional clinical trials using a standardized measure to indicate the real effect of the common bean on health.

Response of maize and common bean to spatial and temporal differentiation in maize-common bean intercropping.

An experiment on maize (Zea mays)-common bean (Phaseolus vulgaris L.) intercropping was conducted for two years (2014 and 2016) at two locations in North western Ethiopia with the objective of determining the spatial arrangement and planting date of common bean. Common bean intercropped with maize at three planting dates (simultaneously with maize, at emergence and knee height of maize) in two spatial arrangements (alternate and paired arrangements).The experimental design was factotrial randomized complete block design with three replications. Sole maize and common bean were included as a check. Results revealed that the spatial and temporal differentiation significantly affect only the agronomic attributes of common bean in common bean-maize intercropping. At Adet the grain yield of common bean (1.9 t ha-1), LER (1.99) and MAI (357) in maize-common bean intercropping was higher when common bean was planted at the same time with maize in paired planting pattern. On the other hand, maximum LER (1.61) and MAI (2.83) at Finoteselam were observed when common bean was intercropped with maize at maize emergence in paired planting pattern. Simultaneous intercropping of common bean with maize gave more stable total land output yield as compared to other intercropping systems but showed high variability as compared to the sole cropping. Thus, it can be concluded that planting common bean simultaneously with maize in paired planting pattern at Adet and planting common bean at maize emergence at Finoteselam in maize-common bean intercropping gave maximum land use efficiency and profitability of the cropping system without reducing the main crop yield (maize).This research also suggested further research on the compatibility of various maize and common bean varieties in different spatial and temporal differentiation.

Rapid specialization of counter defenses enables two-spotted spider mite to adapt to novel plant hosts.

Genetic adaptation, occurring over a long evolutionary time, enables host-specialized herbivores to develop novel resistance traits and to efficiently counteract the defenses of a narrow range of host plants. In contrast, physiological acclimation, leading to the suppression and/or detoxification of host defenses, is hypothesized to enable broad generalists to shift between plant hosts. However, the host adaptation mechanisms used by generalists composed of host-adapted populations are not known. Two-spotted spider mite (TSSM; Tetranychus urticae) is an extreme generalist herbivore whose individual populations perform well only on a subset of potential hosts. We combined experimental evolution, Arabidopsis thaliana genetics, mite reverse genetics, and pharmacological approaches to examine mite host adaptation upon the shift of a bean (Phaseolus vulgaris)-adapted population to Arabidopsis. We showed that cytochrome P450 monooxygenases are required for mite adaptation to Arabidopsis. We identified activities of two tiers of P450s: general xenobiotic-responsive P450s that have a limited contribution to mite adaptation to Arabidopsis and adaptation-associated P450s that efficiently counteract Arabidopsis defenses. In approximately 25 generations of mite selection on Arabidopsis plants, mites evolved highly efficient detoxification-based adaptation, characteristic of specialist herbivores. This demonstrates that specialization to plant resistance traits can occur within the ecological timescale, enabling the TSSM to shift to novel plant hosts.

Abscisic acid implicated in differential plant responses of Phaseolus vulgaris during endophytic colonization by Metarhizium and pathogenic colonization by Fusarium.

Metarhizium robertsii is an insect pathogen as well as an endophyte, and can antagonize the phytopathogen, Fusarium solani during bean colonization. However, plant immune responses to endophytic colonization by Metarhizium are largely unknown. We applied comprehensive plant hormone analysis, transcriptional expression and stomatal size analysis in order to examine plant immune responses to colonization by Metarhizium and/or Fusarium. The total amount of abscisic acid (ABA) and ABA metabolites decreased significantly in bean leaves by plant roots colonized by M. robertsii and increased significantly with F. solani compared to the un-inoculated control bean plant. Concomitantly, in comparison to the un-inoculated bean, root colonization by Metarhizium resulted in increased stomatal size in leaves and reduced stomatal size with Fusarium. Meanwhile, expression of plant immunity genes was repressed by Metarhizium and, alternately, triggered by Fusarium compared to the un-inoculated plant. Furthermore, exogenous application of ABA resulted in reduction of bean root colonization by Metarhizium but increased colonization by Fusarium compared to the control without ABA application. Our study suggested that ABA plays a central role in differential responses to endophytic colonization by Metarhizium and pathogenic colonization by Fusarium and, we also observed concomitant differences in stomatal size and expression of plant immunity genes.

Genome-wide association analysis of bean fly resistance and agro-morphological traits in common bean.

The bean fly (Ophiomyia spp) is a key insect pest causing significant crop damage and yield loss in common bean (Phaseolus vulgaris L., 2n = 2x = 22). Development and deployment of agronomic superior and bean fly resistant common bean varieties aredependent on genetic variation and the identification of genes and genomic regions controlling economic traits. This study's objective was to determine the population structure of a diverse panel of common bean genotypes and deduce associations between bean fly resistance and agronomic traits based on single nucleotide polymorphism (SNP) markers. Ninety-nine common bean genotypes were phenotyped in two seasons at two locations and genotyped with 16 565 SNP markers. The genotypes exhibited significant variation for bean fly damage severity (BDS), plant mortality rate (PMR), and pupa count (PC). Likewise, the genotypes showed significant variation for agro-morphological traits such as days to flowering (DTF), days to maturity (DTM), number of pods per plant (NPP), number of seeds per pod (NSP), and grain yield (GYD). The genotypes were delineated into two populations, which were based on the Andean and Mesoamerican gene pools. The genotypes exhibited a minimum membership coefficient of 0.60 to their respective populations. Eighty-three significant (P<0.01) markers were identified with an average linkage disequilibrium of 0.20 at 12Mb across the 11 chromosomes. Three markers were identified, each having pleiotropic effects on two traits: M100049197 (BDS and NPP), M3379537 (DTF and PC), and M13122571 (NPP and GYD). The identified markers are useful for marker-assisted selection in the breeding program to develop common bean genotypes with resistance to bean fly damage.

Insights into role of STP13 in sugar driven signaling that leads to decrease in photosynthesis in dicot legume crop model (Phaseolus vulgaris L.) under Fe and Zn stress.

Mineral (Fe/Zn) stress significantly affects fundamental metabolic and physiological responses in plants that results in reduction of plant growth and development. Deficiency of these micronutrients leads to inhibition of photosynthesis by having impact on various crucial biological processes like protein synthesis, primary and secondary metabolism and carbohydrate partitioning between source and sink tissues. In the present study, common bean variety Shalimar French Bean-1 (SFB-1) plants were used as an experimental material and were grown under in vitro condition on four different MGRL media i.e. normal MGRL medium (Control), MGRL without Fe (0-Fe), MGRL without Zinc (0-Zn) and MGRL with excess Zn (300-Zn) for 21 days under optimum conditions. Shoot and root tissues from all the treatments were harvested and further subjected to estimation of total chlorophyll, total sugar and extraction of total RNA for differential gene expression of sugar transporter 13 (STP13). We observed significant decrease in total chlorophyll content in samples harvested from mineral stress plants. However, the concentration of total sugar and fold expression of STP13 gene was significantly higher in shoots of Fe/Zn stressed and in roots of 300-Zn plants. We observed higher accumulation of sugar under stress condition that correlated with high expression of sugar transporter 13 (STP 13). Further, we observed decrease in the chlorophyll content under stress conditions. Based on these findings, we propose the role of sugar driven signaling in decreasing photosynthesis in case of common bean. The decrease in photosynthesis is confirmed by observing significant decrease in chlorophyll content in stressed plants.

Contrasting anther glucose-6-phosphate dehydrogenase activities between two bean varieties suggest an important role in reproductive heat tolerance.

Common beans (Phaseolus vulgaris) are highly sensitive to elevated temperatures, and rising global temperatures threaten bean production. Plants at the reproductive stage are especially susceptible to heat stress due to damage to male (anthers) and female (ovary) reproductive tissues, with anthers being more sensitive to heat. Heat damage promotes early tapetal cell degradation, and in beans this was shown to cause male infertility. In this study, we focus on understanding how changes in leaf carbon export in response to elevated temperature stress contribute to heat-induced infertility. We hypothesize that anther glucose-6-phosphate dehydrogenase (G6PDH) activity plays an important role at elevated temperature and promotes thermotolerance. To test this hypothesis, we compared heat-tolerant and susceptible common bean genotypes using a combination of phenotypic, biochemical, and physiological approaches. Our results identified changes in leaf sucrose export, anther sugar accumulation and G6PDH activity and anther H2 O2 levels and antioxidant-related enzymes between genotypes at elevated temperature. Further, anther respiration rate was found to be lower at high temperature in both bean varieties. Overall, our results support the hypothesis that enhanced male reproductive heat tolerance involves changes in the anther oxidative pentose phosphate pathway, which supplies reductants to critical H2 O2 scavenging enzymes.

Genome-wide analysis and expression profiling of H-type Trx family in Phaseolus vulgaris revealed distinctive isoforms associated with symbiotic N2-fixing performance and abiotic stress response.

Thioredoxins (Trxs) are implicated in plant development and stress tolerance through redox regulation of target proteins. Trxs of Type h (Trxhs) constitute the largest and the most complicated cluster in the Trx family because of their unknown individual functions. Here, we identified and characterized the Phaseolus vulgaris Trxh family during development, mutualistic interactions and in response to abiotic stress. P. vulgaris (common bean) Trxh gene family (PvTrxh) encompasses 12 isoforms (PvTrxh1-h12), subdivided into 3 groups according to their amino acid sequence features. In silico RNA-seq -based expression analysis showed a differential expression of PvTrxh genes during development. RT-qPCR analysis of PvTrxh genes during nodule organogenesis revealed their highest expression in the nodule primordium (NP). Interestingly, in response to symbiosis, specific PvTrxh isoforms (PvTrxh3 and h5) were found to be highly upregulated compared to mock-inoculated plants. In addition, their expression patterns in the NP positively correlated with the symbiotic N2-fixing efficiency of the Rhizobium strain, as revealed by a number of symbiotic efficiency parameters (ARA, leghemoglobin content, biomass, and total soluble proteins), concomitantly with increased amounts of hydrogen peroxide (H2O2). On the other hand, distinctive PvTrxh isoforms were found to be upregulated in plant leaves, where H2O2 amounts were elevated, in response to both salt and drought constraints. When exogenously applied, H2O2 upregulated specific PvTrxh isoforms in plant leaves and roots. These findings point to a specific, rather than redundant, function for Trxh proteins in common bean beside the association of distinctive Trxh isoforms with symbiosis and abiotic stress response.

Regulation of flowering under short photoperiods based on transcriptomic and metabolomic analysis in Phaseolus vulgaris L.

Common bean (Phaseolus vulgaris L.) is a short-day plant and its flowering time, and consequently, pod yield and quality is influenced by photoperiod. In this study, the photoperiodic-sensitive variety 'Hong jin gou', which flowers 31 days (d) earlier in short-day than in long-day, was used as the experimental material. Samples were collected to determine the growth and photosynthetic parameters in each daylength treatment, and transcriptome and metabolome data were conducted. We identified eight genes related to flowering by further screening for differentially expressed genes. These genes function to regulate the biological clock. The combination of differentially expressed genes and metabolites, together with the known regulation network of flowering time and the day-night expression pattern of related genes allow us to speculate on the regulation of flowering time in the common bean and conclude that TIMING OF CAB EXPRESSION1 (TOC1) plays a pivotal role in the network and its upregulation or downregulation causes corresponding changes in the expression of downstream genes. The regulatory network is also influenced by gibberellic acid (GA) and jasmonic acid (JA). These regulatory pathways jointly comprise the flowering regulatory network in common bean.

Genetic dissection of drought resistance based on root traits at the bud stage in common bean.

KEY MESSAGE: A whole-genome resequencing-derived SNP dataset used for genome-wide association analysis revealed 196 loci significantly associated with drought stress based on root traits. Candidate genes identified in the regions of these loci include homologs of known drought resistance genes in A. thaliana. Drought is the main abiotic constraint of the production of common bean. Improved adaptation to drought environments has become a main goal of crop breeding due to the increasing scarcity of water that will occur in the future. The overall objective of our study was to identify genomic regions associated with drought resistance based on root traits using genome-wide association analysis. A natural population of 438 common bean accessions was evaluated for root traits: root surface area, root average diameter, root volume, total root length, taproot length, lateral root number, root dry weight, lateral root length, special root weight/length, using seed germination pouches under drought conditions and in well-watered environments. The coefficient of variation ranged from 11.24% (root average diameter) to 38.19% (root dry weight) in the well-watered environment and from 9.61% (root average diameter) to 39.05% (lateral root length) under drought stress. A whole-genome resequencing-derived SNP dataset revealed 196 loci containing 230 candidate SNPs associated with drought resistance. Seventeen candidate SNPs were simultaneously associated with more than two traits. Forty-one loci were simultaneously associated with more than two traits, and eleven loci were colocated with loci previously reported to be related to drought resistance. Candidate genes of the associated loci included the ABA-responsive element-binding protein family, MYB, NAC, the protein kinase superfamily, etc. These results revealed promising alleles linked to drought resistance or root traits, providing insights into the genetic basis of drought resistance and roots, which will be useful for common bean improvement.