Characterization of Rhizobium and Plant Growth Promoting Rhizobacteria from French Bean Rhizosphere and Their Effect on French Bean Productivity

French bean (Phaseolus vulgaris L.) is used profusely by the common people as an alternative diet of protein. The sparse nodulation in French bean mainly may be due to lack of threshold level of specific rhizobial cells in soil at the time of sowing. The isolates streaked on YEMA with BTB changed to yellow color showing the production of acid which is the characteristic of Rhizobium. Utilization of different carbon sources is an efficient tool to characterize the isolates. Plant growth promoting rhizobacteria is the beneficial rhizobacteria inoculation of which increases growth and yield of French bean through different direct and indirect mechanisms. Inoculation of French beans with rhizobial and rhizobacterial isolates found to be improved growth, physiological, quality parameters and grain yield through symbiotic N2-fixation capacity and plant growth promoting abilities. Co-inoculation of rhizobial and rhizobacterial isolates enhanced the growth and grain yield of French bean. These isolates may be used as consortium to improve the growth of French bean, which may reduce the dependency of farmer on chemical fertilizer as well as risk of pollution. In this chapter characterization of Rhizobium and plant growth promoting rhizobacteria and their effect on plant growth has been reviewed.

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.

A Dwarf French Bean - Anisia

Phaseolus vulgaris is one of the most important vegetables with high nutritional value consisting in proteins, iron, magnesium, folic acid and complex carbohydrates. The aim of this study was to obtained a dwarf french bean genotype with the following characteristics: yield and quality potential, earliness and extreme environmental conditions. The variety was obtained by repeated individual selection and now is submitted to the conservative selection program. For all agro-morphological characters, descriptive statistics were calculated. The pods of Anisia beans are yellow and have a simultaneous maturation, easing the harvesting process. The average weight of a pod at consumption maturity was 4.23 g. The yield potential of fresh pods varies between 18-20 t/ha. From our studies, Anisia cultivar is suitable for cultivation both organically and conventionally. The research has been completed with obtaining of a new variety of dwarf french bean that has been registered in the Official Catalogue of Romanian Crop Plants under the name ‘Anisia’. The variety has a distinct phenotypic expressiveness with a high yield and quality potential.

First Report of Alternaria alternata Causing Leaf Spot on Kidney Bean in China

Kidney bean (Phaseolus vulgaris), also being known as common bean, dry bean or french bean, is one of the most precious and highly nutritious legume crop cultivated and consumed worldwide(Blair et al.,2012; Choudhary et al.,2018) , which is an important edible foods or one of the most economically important vegetable crops in China. It is widely grown in the Heilongjiang Province in China. In July of 2020, leaf spot symptoms were found on the old or new leaves of Kidney bean plants (Phaseolus vulgaris L.) in our experimental fields located in Zhaozhou County(N45°42 '20.16 ", E125°15' 58.63" ), Daqing City, Heilongjiang Province, China. This field had disease incidences of approximately 20%. The leaf spot is conducive to the onset at high temperature and humidity environment, and this disease spreads very quickly after rainy days, therefore it is potentially a large risk for the development of Kidney bean industry. In its early occurrence phase, the infected leaves showed yellowish halo on the leaves, in which the middle mesophyll lost green. Thereafter, the yellow halo turned brown, and the middle leaf tissue of the halo appeared brown, ultimately the whole leaves had many brown spots (Supplementary Figure S1). To isolate the pathogen, diseased tissue (5×5 mm) was excised from the margins of individual lesions from the leaves of diseased plants with typical symptoms, and was disinfected with 75% ethanol for 10s followed by 2% NaClO for 3 min and then washed five to eight times with sterile water. Afterwards, the samples were transferred to potato dextrose agar (PDA) plates and incubated. After 5 to 7 days of incubation at 25°C (Wei et al.,2018), the mycelia were dark green with white margins in obverse and dark in reverse. Conidiophores were light brown with 2 to 4 septa and obclavate, 17.5to 44.0 × 6.5 to 14.5μm, with a short beak, and with 1 to 5 transverse septa and 0 to 2 longitudinal septa, light brown to olive-brown (Supplementary Figure S2). Based on morphological features and sporulation pattern, the pathogen was similar to characteristics described Alternaria alternate (Zhou et al,2014), being identified as A. alternata. To confirm pathogenicity, the isolates were cultured on PCA for 7days to prepare conidial suspensions, then being produced a final concentration of 1×108 spores/ml. Five potted Kidney bean plants were sprayed with conidial suspensions, and five control potted plants were sprayed with sterile distilled water, in which these potted Kidney bean plants were treated after wiping each leaf surface with 75% ethanol and washing each leaf with sterilized distilled water five times. These plants were incubated in an artificial growth chamber at 26 to 28°C with a 12 h light/dark photoperiod, with 85% relative humidity. After 3 days, yellowish halo lesions appeared on the inoculated plants, and pale lesions with distinct dark brownish red borders on Kidney bean leaves were observed after eight days, but no lesions were observed on the control leaves. Pathogenicity tests were repeated three times. The internal transcribed spacer (ITS) region of rDNA was amplified and sequenced with primers ITS1/ITS4. BLAST analysis of the sequences showed 100% sequence identity with a pathogenic A. alternata (Fr.) Keissl (Supplementary Figure S3), and the nucleotide sequence of the ITS region was submitted to GenBank under accession MZ951052. In China, there are no detailed records about the causal agent of this disease on Kidney bean in a paper in Chinese. To our knowledge, this is the first confirmed report of leaf spot causing by A. alternata on Kidney bean in China.

Screening of French Bean (Phaseolus vulgaris L.) Genotypes against Alternaria Leaf Spot Caused by (Alternaria alternata) under Dryland Conditions of Kashmir

Sixty-three genotypes of french bean was screened against leaf spot (Alternaria alternata) in sick plots at Research Farm of Dryland Agriculture Research Srinagar, Rangreth during Kharif 2018 and 2019. The highest mean disease incidence ranged from 0.00 to 85.00 per cent with the mean disease intensity ranged from 0.00 to 53.26 per cent .One genotype namely ‘Local Pulwama’ was highly susceptible in their disease reaction. Among the screened germplasm, ‘Highly Resistant’ genotypes was SKU-R-601, SKUA-R-105, SKU-R-927, DARS-25, DARS-66, DARS-R-615, while as ‘Susceptible’ genotypes was DARS-8, DARS-12, DARS-11, SKUAST-R-155, SKU-R-928, DARS-7, DARS-R-4, Bhaderwah (L), Local Kupwara black and Raj Jawala. Local Pulwama was found to be a highly susceptible (HS) genotype. Twenty nine genotypes namely., DARS-16, DARS-9, DARS-54, DARS-39, VL-125, DARS-63, ENTO-504, SKUAST-204,SKU-R-925, DARS-60, DARS-109, DARS-43, DARS-44, SKU-R-23, DARS-4, DARS-74, SKU-R-105, DARS-40, DARS-23, DARS-18, SKU-R-71, WB-341, SKU-R-605, Uri local, Shopian (L), SKU-R-23, DARS-71, SSGB-729, DARS-R-19 showed resistant reaction to disease. The selection for resistance was based on the reaction of varieties on leaves.

Impact of Organic Seed Priming Amendments and Botanicals on Seed Quality Parameters of French Bean (Phaseolous vulgaris L.)

The current experiment was conducted to evaluate the Performance of Organic amendments and botanical treatments on seed quality parameters of French bean under stimulated environmental conditions. An experiment was conducted in 2021 at postgraduate seed testing laboratory, Department of Genetics and Plant Breeding Naini Agriculture Institute, Sam Higginbottom University of Agriculture Technology and Sciences, Prayagraj. The French bean Cultivar Arka Bold seeds were used for priming. Organic treatments are designated as Panchagavya 2%, 4%,6%,8%, Agniasthra 2%,4%,6%,8% and Botanicals treatments are Tulasi leaf extract 5%, Aloevera leaf extract 5%, Vinca rosea leaf extract 5% and also did hydroprming treatment using distilled water respectively. Seeds were soaked in organic, botanicals and in distilled water for duration of 6 hours followed by shade drying. The results were obtained and it was found that all the treatments showed significant effect on quality parameters. The highest was found in panchgavya of all doses followed by tulasi leaf extract found to be best in Germination percentage, Speed of Germination, Root length, Shoot length, Seedling length, Seed vigour index-I, Seed vigour Index-II compared to control or untreated seeds which indicates the effect of organics and botanicals on physiological processes of the seeds. This study revealed that priming with organic amendments and botanicals can be effective in enhancing the seed quality parameters of french bean and they are low cost, effective and nature friendly and toxic free.

Exogenous Application of Methyl Jasmonate and Salicylic Acid Mitigates Drought-Induced Oxidative Damages in French Bean (Phaseolus vulgaris L.)

Drought stress impairs the normal growth and development of plants through various mechanisms including the induction of cellular oxidative stresses. The aim of this study was to evaluate the effect of the exogenous application of methyl jasmonate (MeJA) and salicylic acid (SA) on the growth, physiology, and antioxidant defense system of drought-stressed French bean plants. Application of MeJA (20 μM) or SA (2 mM) alone caused modest reductions in the harmful effects of drought. However, combined application substantially enhanced drought tolerance by improving the physiological activities and antioxidant defense system. The drought-induced generation of O2●− and H2O2, the MDA content, and the LOX activity were significantly lower in leaves when seeds or leaves were pre-treated with a combination of MeJA (10 μM) and SA (1 mM) than with either hormone alone. The combined application of MeJA and SA to drought-stressed plants also significantly increased the activities of the major antioxidant enzymes superoxide dismutase, catalase, peroxidase, glutathione peroxidase, and glutathione-S-transferase as well as the enzymes of the ascorbate–glutathione cycle. Taken together, our results suggest that seed or foliar application of a combination of MeJA and SA restore growth and normal physiological processes by triggering the antioxidant defense system in drought-stressed plants.