Bitter Gourd Plants Research Articles

Genome-Wide Analysis of the Serine Carboxypeptidase-like (SCPL) Protein Family of Bitter Gourd and Functional Validation of McSCPL22 in Fusarium oxysporum f. sp. Momordicae (FOM) Resistance.

Bitter gourd is increasingly being recognized for its value as a vegetable and medicinal use, but the molecular mechanisms of pathogen resistance remain relatively poorly understood. The serine carboxypeptidase-like (SCPL) protein family plays a key role in plant growth, pathogen defense, and so on. However, a comprehensive identification and functional characterization of the SCPL gene family has yet to be conducted in bitter melon. In this study, 32 SCPL genes were identified in bitter gourd and divided into three classes. The number of SCPL genes contained in the three clusters was 7, 7, and 18, respectively. Most SCPL gene promoters contain cis-acting elements with light, hormone, and stress responses. The RNA sequencing data showed that the expression of several SCPL genes changed significantly after pathogen infection. In particular, expression of the McSCPL4, 10, 17, 22, and 25 genes increased substantially in the resistant varieties after infection, and their expression levels were higher than those in the susceptible varieties. These results suggested that genes such as McSCPL4, 10, 17, 22, and 25 may play a significant role in conferring resistance to fungal infections. Moreover, the expression levels of the McSCPL10, 17, 22, 23, and 25 genes were likewise significantly changed after being induced by salicylic acid (SA) and jasmonic acid (JA). In situ hybridization showed that McSCPL22 was expressed in the vascular tissues of infected plants, which largely overlapped with the location of Fusarium oxysporum f. sp. Momordicae (FOM) infection and the site of hydrogen peroxide production. Our results showed that McSCPL22 may be involved in the regulation of the SA and JA pathways and enhance resistance to FOM in bitter gourd plants. This is the first study to perform SCPL gene family analysis in bitter gourd. McSCPL22 may have the potential to enhance FOM resistance in bitter gourd, and further investigation into its function is warranted. The results of this study may enhance the yield and molecular breeding of bitter gourd.

Rapid Construction and Application of a Vector for Tobacco Ringspot Virus-Induced McPDS Silencing in Bitter Gourd

The aim of this study is to facilitate the construction of virus-induced gene silencing vectors and to provide a reference or positive control for gene silencing in bitter gourd. A recombinant TRSV (tobacco ringspot virus) containing two components, pTRSV1 and pTRSV2, was used in this study. The fragment of the McPDS target was cloned into pTRSV2 via combined enzymic ligation during digestion. The TRSV components were agro-infiltrated into tobacco leaves to grow virus particles, which were then extracted and mechanically inoculated into the bitter gourd plants. The effect of TRSV-McPDS-mediated McPDS gene silencing was evaluated by observing the photo-bleaching phenotype, detecting the TRSV virus, and quantifying the downregulation of MCPDS gene expression and chlorophyll contents. The results showed that all bitter gourd plants infected with the empty TRSV or TRSV-McPDS virus grew and developed normally, with no visible signs of viral disease. However, after seven days of inoculation, only the bitter gourd plants that were inoculated with TRSV-McPDS showed obvious photobleaching in the leaves, stems, and buds. The TRSV-specific fragments were tested out in the systemically infected leaves of bitter gourd. The transcription level of the McPDS gene in the leaves dropped by 84.7%. The chlorophyll content also dropped significantly. These data suggest that the rapidly constructed VIGS vector TRSV-McPDS successfully induced McPDS silencing in bitter gourd. Taken together, the results of this study provide a practical method for vector construction in various VIGS applications, as well as a reference and a positive control for TRSV-induced gene silencing in bitter gourd.

Effects of pre-harvest chitosan application on growth parameters and total phenolic - antioxidant contents of bitter gourd (Momordica charantia L.)

Bitter gourd (Momordica charantia L.) plant is cultivated for both culinary and medicinal purposes in the world due to its valuable benefits for health-promoting properties. The current study aimed to reveal the effects of chitosan applied at three different concentrations (50 ppm, 100 ppm, and 150 ppm) in three different treatments with 21 days intervals on growth parameters and total phenolic and antioxidant contents of bitter gourd. The findings of the study demonstrated that the foliar treatment with 100 ppm chitosan at the second and third treatments had positive effects on the majority of growth parameters examined and on increasing total phenol and antioxidants in bitter gourd. As a result, chitosan could be a possible substance to be used to enhance bitter gourd plants’ growth and development as well as in several industrial fields such as pharmaceuticals and agriculture.

Momordica charantia (bitter gourd), a potent antidiabetic phytomedicine

Gourd bitter Grown mostly in India, China, and Southeast Asia, the tropical creeping plant known as or bitter melon. Its edible fruit is the primary reason for the plant's cultivation. Because of their bitter flavour, bitter gourds are not well-liked. The fruits of the Cucurbitaceae family plant Momordica charantia are a good source of a number of important nutrients. Over sixty phytomedicines, including blood purifiers, antioxidants, anticancer agents, and diabetes inhibitors, are present in the entire plant. In-depth information about the nutritional elements, different bioactive substances, and significant nutraceutical qualities of the bitter gourd plant in relation to diabetes are attempted to be provided in this review.

Molecular characterization of a novel polerovirus from bitter gourd plants and dynamic subcellular localization of the virus-encoded proteins

Viruses within the Polerovirus genus in the family of Solemoviridae have a single-stranded positive-sense RNA genome of about 5.6–6.2 kb in length. In this study, the bitter gourd leaves showing yellowing and crumple symptoms were collected for small RNAs (sRNAs) sequencing. Analysis of the contigs de novo assembled from sRNA-sequencing data, followed by RT-PCR and cloning, determined the complete viral genome to be 5665 nucleotides. This virus isolate contains conserved ORF3a, ORF3, ORF4, and other typical features of poleroviruses. The P0 protein of this virus isolate shares less than 74.80% amino acid sequence identity with any of the previously characterized poleroviruses, indicating that it should be a novel polerovirus. We name this virus as bitter gourd yellowing crumple virus (BYCV). We further revealed the dynamic subcellular localization and protein accumulation of seven proteins encoded by BYCV in Nicotiana benthamiana plants over time, and these viral proteins displayed specific subcellular localization. Expressing the BYCV P0 protein using a potato virus X vector caused severe symptoms in N. benthamiana plants, while P0 exhibited weak RNA silencing suppression activity. These findings provide an example for investigating the dynamic subcellular localizations of viral proteins and demonstrate that P0 is a critical protein potentially playing an important role in virus infection.

Coumarin regulated redox homeostasis to facilitate phytoremediation of saline and alkaline soils by bitter gourd (Momordica charantia L.).

The use of coumarin (COU) to alleviate the phytotoxic effects of salinity has great potential in improving the phytoremediation of saline and alkaline soils. 30-day bitter gourd plants were exposed to 15 dS m‒1 salinity of neutral (NaCl and Na2SO4) and alkaline (Na2CO3 and NaHCO3) salts. 60-day plants were harvested to record different growth, physiological and biochemical attributes. Salinity significantly subsided plant growth, chlorophyll, photosynthesis, and nutrient acquisition. Salinity induced notable oxidative damage in plants that displayed higher relative membrane permeability (RMP), accumulated elevated ROS (H2O2 and O2•‒) and MDA levels alongside intensified lipoxygenase (LOX) activity. The production of cytotoxic methylglyoxal was also significantly higher in plants under salinity. COU seed priming (50, 100 and 150mg L‒1) promoted plant growth by circumventing oxidative injury and intensifying oxidative defense. Further, COU maintained the intricate balance between reduced (GSH) and oxidized (GSSG) glutathione to diminish ion excess toxicity, thereby facilitating the phytoremediation of saline soils. The lower doses of COU promoted methylglyoxal and ROS detoxification systems that, in turn, lessened the phytotoxic effects of salinity. COU restored ions homeostasis by augmenting osmotic adjustment in plants under salinity.

Education on the Utilization of Stingless Bees as Potential Natural Pollinators for Bitter Gourd Plants

his activity aims to provide solutions to the problems faced by the community in the agricultural sector. In this case, the help of pollination by stingless bees is a solution to the quality and quantity of agricultural crop yields, especially bitter melon plants grown by the community. The selection of stingless bees as pollinating agents is based on safety and convenience reasons for the community in participating in a series of activities. These bees are adaptive and easy to manage. The activity method is participatory action research (PAR) which actively involves the community from the preparatory stage, the process, to the final stage. Activity evaluation includes context, input, process, and product. The result of this activity is that the community understands the technique of using pollinating bees to optimize bitter melon crop yields. Through this activity the community also understands the importance of maintaining bee populations in nature. The positive impact that can be expected from this activity is an increase in the quality and quantity of bitter melon yields in the form of fruit size, number of fruit, and number of seeds. Furthermore, the community took the initiative to plant other types of agricultural crops and reuse stingless bees as the main pollinating agent.

Impact of Polyhouse on Production Potential of Bitter Gourd in Off-season

In Bangladesh, the bitter gourd, which is a vegetable, is a wonderful source of magnesium, folate, zinc, phosphorus, and vitamins B1, B2, and B3. It also contains a high level of dietary fiber. From December 2020 to April 2021, an experiment was carried out in the field laboratory of Bangladesh Agricultural University, Mymensingh, to determine how the polyhouse and the local environment affected the growth and yield of bitter gourd during the off-season. It was a factorial experiment using RCBD (Randomized Completely Block Design), in which Factor A represented the impact of a polyhouse and Factor B represented the influence of the environment on the development and yield of bitter gourd during the off-season. Results showed that photochemically active radiation decreased within the polyhouse compared to the open area outside. In terms of soil temperature, soil moisture, and air temperature, a reverse trend was seen. In comparison to an open field during the winter, the polyhouse had higher air, soil, and soil moisture temperatures. Compared to plants cultivated in open fields, bitter gourd plants planted in poly houses had longer stems, more branches, blooms, and higher reproductive efficiency, which led to more fruit setting plants-1 and a higher fruit yield. Additionally, the fruit size in the polyhouse was greater than it was in the open field situation. In comparison to open fields, the fruit output of bitter gourd was approximately 2.5 times higher in polyhouses, which will be helpful to meet up the nutritional demand in the off-season.

DETERRENCE EFFECT OF COLORED DIVERSION SHEETS ON THE POPULATION DENSITY OF MELON FRUIT FLIES BACTROCERA CUCURBITAE (COQUILLETT) AND YIELD PARAMETERS OF BITTER GOURD (MOMORDICA CHARANTIA L.)

The bitter melon, or the bitter gourd (Momordica charantia L.), is a tropical and subtropical area vegetable. Bactrocera cucurbitae (Coquillett), causes 30 to 100% crop loss. This study used refractive color sheets to examine reduced-risk insecticide spinosad formulations of prevalence and infestation of fruit flies on bitter gourd plants. Three different angles (30°, 60°, and 90°) of reflective sheets were put in M. charantia beds. Results showed that fruit flies were substantially more prevalent (60%) in the control condition. Compared to other color sheets, treatments using yellow refractive sheets showed the highest occurrence of fruit flies. Spinosad, a low-risk insecticide, had the lowest fruit FI% (6%) and the highest commercial yield (860g/bed), followed by blue-colored refractive sheets. Installation angles had no appreciable impact on any of the examined characteristics. Additionally, treatments using yellow-colored refractive sheets and the spinosad formulation (1:1.8), (1:4.9) were found to have the highest and lowest CBR. Installing refractive sheets in colors other than yellow at angles of 30° or 60° has been determined to be a more successful and cost-efficient technique for reducing fruit fly incidence on several vegetable crops. This is especially true when combined with biorational insecticides like spinosad.

Novel sources of resistance to fusarium wilt in Luffa species.

Fusarium wilt is a serious disease of cucurbit crops including cultivated Luffa species (Luffa aegyptiaca, Luffa acutangula) causing considerable amount of reduction in yield and quality. Luffa is starting to be used as rootstocks for major commercial cucurbit crops, but little is known of its resistance against soilborne diseases. Here, 63 Luffa accessions from the World Vegetable Center genebank were evaluated for resistance to an aggressive isolate of Fusarium oxysporum f. FoCu-1 (Fsp-66). According to visual screening based on disease severity rating, 14 accessions exhibited a high level of resistance against Fsp-66. These accessions were further evaluated for resistance against Fsp-66 and two more isolates FoCu-1 (isolated from infected cucumber plants) and FoM-6 (isolated from infected bitter gourd plants). Of the 14 accessions, 11 were confirmed resistant against isolate Fsp-66. In addition, 13 accessions showed high resistance against isolates FoCu-1 and FoM-6. This is the first report of Fusarium wilt resistance in Luffa and these sources will be valuable for the development of Luffa rootstocks/cultivars resistant to soil-borne pathogen to manage this serious disease.

Interference with sex expression, estimation of yield and bioactive compounds in bitter gourd under PGRs-induced conditions

BackgroundThe bitter gourd fruit yields are not at a desirable level due to maleness. Maleness is one of the biggest difficulties with bitter gourd, reducing fruit yields substantially. On the other hand, plant stages are the most important consideration for PGR application because of their sensitive responsiveness. Therefore, it is necessary to determine how bitter gourd plants respond to plant growth regulators, namely PGR0 (control: application of water as control treatment), PGR1 (GA3-Gibberellic acid, 100 mgL−1), PGR2 (NAA-Naphthalene acetic acid, 100 mgL−1), and PGR3 (MH- Maleic hydrazide, 100 mgL−1) at three application phases, S1: soaking of seeds; S2: four-leaf; and S3: flower bud in terms of vegetative development, male–female flower sex alteration, and fruit features including bioactive compounds.ResultsPhysiological, floral and yield characteristics of bitter gourd exposed significant changes by GA3 and MH at various stages. The number of leaves plant−1, the fresh mass of the plant, and the fresh mass of fruit and fruit dry matter content were enhanced remarkably for MH application at the seed soaking stage except for plant height and the number of branches plant−1. MH increased the number of female flowers plant−1, the number of fruits plant−1 and the yield at the 4-leaf stage of application. PGRs substantially influenced the quantity of sugar, chlorophyll, total carotenoids, protein, and water content at various phases of their application but not on ascorbic acid, TSS, or total phenol concentration.ConclusionsFor sex expression and yield attributes, 100 mgL−1 MH at the 4-leaf stage would be effective in bitter gourd. Exogenous NAA showed a considerable dual influence on plant development and antioxidant enzyme activity in bitter gourd fruits.

The FomYjeF Protein Influences the Sporulation and Virulence of Fusarium oxysporum f. sp. momordicae.

Fusarium oxysporum causes vascular wilt in more than 100 plant species, resulting in massive economic losses. A deep understanding of the mechanisms of pathogenicity and symptom induction by this fungus is necessary to control crop wilt. The YjeF protein has been proven to function in cellular metabolism damage-repair in Escherichia coli and to play an important role in Edc3 (enhancer of the mRNA decapping 3) function in Candida albicans, but no studies have been reported on related functions in plant pathogenic fungi. In this work, we report how the FomYjeF gene in F. oxysporum f. sp. momordicae contributes to conidia production and virulence. The deletion of the FomYjeF gene displayed a highly improved capacity for macroconidia production, and it was shown to be involved in carbendazim's associated stress pathway. Meanwhile, this gene caused a significant increase in virulence in bitter gourd plants with a higher disease severity index and enhanced the accumulation of glutathione peroxidase and the ability to degrade hydrogen peroxide in F. oxysporum. These findings reveal that FomYjeF affects virulence by influencing the amount of spore formation and the ROS (reactive oxygen species) pathway of F. oxysporum f. sp. momordicae. Taken together, our study shows that the FomYjeF gene affects sporulation, mycelial growth, pathogenicity, and ROS accumulation in F. oxysporum. The results of this study provide a novel insight into the function of FomYjeF participation in the pathogenicity of F. oxysporum f. sp. momordicae.

First report of Fusarium equiseti causing leaf spots of Bitter gourd (Momordica charantia) in Pakistan.

Bitter gourd (Momordica charantia L.) is an important vegetable crop of the Cucurbitaceae family widely cultivated in Pakistan and around the world. In October 2020, a nutrition management trial of Bitter gourd cv. Seminis-200) was conducted on an area of 10,860 sq. ft. (99×110 feet) at the Agricultural Research farm of Bahauddin Zakariya University, Multan (30.2601° N, 71.5158° E), Pakistan. Symptoms of large, brown necrotic leaf spots were observed on the leaves of bitter gourd vines. The disease started from the yellowing of leaves within the reticulate venation and turned brown. Irregular brown leaf spots coalesced to form large necrotic areas followed by foliar chlorosis then wilting that occurred very late. There were no crown rot symptoms although there was slight discoloration of roots and when cut longitudinally, browning of tissues was observed. The disease was assessed visually with 37% incidence which resulted in poor quality and yield in terms of reduced size and yellowing of fruit. Infected vines along with the roots were collected for the isolation of pathogen. A total of 34 leaves and 22 root samples were collected from the field for isolation. The leaf, collar and root portions were cut into 0.5 to 1 cm in length and surface disinfected with 1% sodium hypochlorite (NaOCl) for 2-3 minutes followed by washing twice with autoclaved distilled water and after drying, placed on potato dextrose agar (PDA) medium, and incubated at 25±2 °C for one week. The fungal colonies of fluffy white growth with light orange pigment were isolated. For morphological characterization, a total of 4 pure cultures were isolated from leaves, collar region and root by single spore technique on carnation leaf agar (CLA) medium after 15 days of incubation at 25±2℃. Curved and thick-walled macroconidia with elongated or pointed apical characteristic foot-shaped basal cells were produced in sporodochia. Macroconidia with 5-7 septa measured 22.50-41.80 μm × 2.90-4.20 μm (n = 60). Thick, brown with roughened walls and subglobose ellipsoidal chlamydospores were observed in clumps or chains with the dimension of 5.8 to 10.8 μm (n = 20). On morphological characteristics, the fungus was identified as Fusarium equiseti (Corda) Sacc. according to Leslie and Summerell (2006). Two single spore isolates were used for molecular identification by amplifying ribosomal DNA of the internal transcribed spacer (ITS) region with ITS1/ITS4 primers (White et al. 1990) and for β-tubulin gene region, primers T1/Bt-2b (O'Donnell and Cigelnik, 1997) were used. The obtained sequences were deposited in GenBank with accession numbers MW880179 and MW880198 from the ITS region and BLAST search in GenBank showed 100 and 98.11% alignment with previously published sequences of F. equiseti with accessions OM992323.1and MT558569.1 respectively. Accession number OM867571from the β-tubulin region showed 100% sequence similarity with F. equiseti with accession MN653163.1. For pathogenicity, macroconidia from 2-week-old cultures on CLA medium were harvested to prepare spore suspension (1 × 106 conidia/ml). Koch's postulates were confirmed on nine bitter gourd plants (cv. Seminis-200) by applying spore suspension of fungal inoculum at 3-4 leaf stage separately on leaves by automizer, on collar region after making incision spore suspension was applied and in the root zone, 20ml spore suspension was added whereas distilled water was used as a control with three replications. Plants were kept under controlled conditions in the greenhouse with 65% to 75% humidity and the temperature was maintained at 32±2 °C for one week. After 7-8 days, inoculated plants began to exhibit symptoms of brown, necrotic leaf spots on the leaves of bitter gourd vines followed by yellowing of leaves that eventually turned brown. Roots showed slight discoloration and browning of vascular bundles and finally, the plants wilted after four weeks. while control plants remained symptomless. The symptoms resembled those noticed in the field. The fungus was re-isolated from leaves, collar region and roots, followed by morphological identification, and finally confirmed as F. equiseti. To the best of our knowledge, this is the first report of a leaf spot caused by F. equiseti in a bitter gourd from Pakistan. If the disease is not managed properly, it may cause a drastic effect on yield under favorable environmental conditions. The pathogen may also damage other cucurbitaceous crops cultivated in the area.

FIRST REPORT OF STEM GUMMOSIS AND LEAF BLIGHT DISEASE IN Momordica charantia CAUSED BY Lasiodiplodia theobromae

Momordica charantia is native to India and tropical Asia. During September 2017- December 2018 field survey was carried out nearly 5 hectares of bitter gourd growing areas in Mysuru taluks and KR Nagar taluks, with incidence of 20-30%. The fungal pathogen responsible for this disease was isolated on the PDA media. Initially colonies were pale grey in colour gradually becoming dark gray, and septate mycelia was observed. Initially conidia were aseptate and glassy later turned to dark brown, two-celled and thick-walled. By considering all these culture characters, the isolated fungus was identified as Lasiodiplodia species. For species level identification, molecular characterisation through PCR using specific ITS1 and ITS4 - rDNA primers was carried out. Phylogenetic tree was constructed based on the data obtained from nBLAST, which confirmed the pathogen as Lasiodiplodia theobromae. In GenBank the representative isolate was deposited (Accession number MN891762.1, MN891763.1). The pathogenicity test was performed on one month old bitter gourd plant inoculated with mycelia suspension of L. theobromae. Identity of pathogen was conformed through re-isolation of pathogen from experimental plant. In vitro fungicidal activity was also carried out. The present work is the first report of stem gummosis and leaf blight disease on bitter gourd caused by L. theobromae.

Pemanfaatan Refugia dengan Metode “Border Plant” Untuk Mengendalikan Hama Lalat Buah pada Tanaman Pare

Fruit flies belong to pests that inflict huge losses on farmers, especially fruit and vegetable growers. Damage caused by this fruit fly causes the fruit to become rotten, several ways have been done to inflict fruit flies in Indonesia, but the use of pesticides is still dominant. other efforts are needed, namely by implementing Integrated Pest Management. One of them is ecosystem manipulation by planting using the "border plant" technique or edge plants surrounding the plant with refugia. The use of this technique aims to get natural enemies and polynators to go to the edge plants to forage and breed. The purpose of the study was to determine the influence of refugia planting with "border plant" treatment in suppressing the intensity of fruit fly pest attacks on bitter gourd plants. The study was conducted with a Randomized Group Design (RAK) where there were 5 treatments (controls, kenikir flowers, paper, marigolds, purslane) and 5 repeats. The results showed that all refugia plants gave good results in suppressing fruit fly pest attacks on bitter gourd indicated by the percentage of attack rate only below 10%, the development of pupae and imago populations produced also showed that the average form was relatively very small, namely below 10 per head.Keywords : Border Plant, Fruit Fly, Bitter Gourd Plant

Insect vectors transmission of phytoplasma to vegetables in Eastern Visayas Philippines

Phytoplasma diseases are found affecting vegetables in Eastern Visayas, Philippines. Identifying the insect vectors that transmit phytoplasma in the field is necessary for the management of this disease. This study was conducted to identify the vectors of phytoplasma affecting bitter gourd, loofah, and string beans. Insects associated with these vegetables that had shown phytoplasma symptoms in the field were collected, mass-reared, and the progenies of mass reared insects were used for transmission to healthy host plants. Phytoplasma detection was done through PCR and nest PCR assays. Phytoplasma was positively transmitted to healthy bitter gourd plants by a cicadellid leafhopper, Hishimonus sp. and brown planthopper, Ricania speculum. The ~ 1.25Kb phytoplasma-specific band was amplified in these insects. The phytoplasmas transmitted by the Hishimonus sp. and R. speculum produced two different types of symptoms to the bitter gourd, and rDNA sequence analysis separated them into two clusters which confirmed that the phytoplasmas belong to two different strains. Although the Aphis gossypii and Aphis craccivora also produced symptoms in bitter gourd and string beans, and the pathogen was detected in the insects, whether they vectored phytoplasma to their respective hosts needs further study, since the symptoms produced were quite different from the ones produced by the cicadellid leafhopper and Ricania speculum.

Improved in planta genetic transformation efficiency in bitter gourd (Momordica charantia L.)

Production of transformed bitter gourd plants through in vitro regeneration is a laborious practice, which may also result in somaclonal variations. Thereby, in the current study, we have established a less tedious in planta protocol for more efficient genetic transformation of bitter gourd var. NBGH-470 (Apurva) using the seed as a target material. Bitter gourd seeds were transformed by Agrobacterium tumefaciens strain LBA4404 bearing the pCAMBIA1301 binary vector, and the transformed plants were selected against hygromycin B. The putatively transformed bitter gourd (To) plants were examined by GUS assay. Two parameters, including vacuum infiltration and sonication improving the in planta transformation, have been investigated in the present work. Amongst several time durations examined, the highest transformation rate (37%) was achieved upon subjecting the pre-cultured bitter gourd seeds to sonication for 15 min, followed by vacuum infiltration for 6 min in LBA4404 culture suspension. The transformed bitter gourd (T1) plants were selected against hygromycin B, and the transgene integration was evaluated by polymerase chain reaction (PCR), Southern hybridization, and reverse transcriptase PCR (RT-PCR). The developed protocol in the current study is suitable to genetically engineer the bitter gourd plants with disease and pest-resistant traits.

Association of cucurbit aphid-borne yellows virus with cucumberplants in India.

The online version of this article (10.1007/s13337-020-00645-4) contains supplementary material, which is available to authorized users.

Evaluation of morphological traits, hormonal metabolism, and transcriptional abundance in bitter gourd (Momordica charantia L.) plants in response to ethephon inducement

Bitter gourd (Momordica charantia L.) is sensitive to phytohormone treatment for organ development and growth. In light of this, we performed this study to evaluate the influence of ethephon at physiological and transcriptional levels. High performance liquid chromatography – tandem mass spectrometry (HPLC-MS/MS) has demonstrated that ethylene biosynthesis was enhanced by increased ACC synthase (ACS) activity and 1-aminocyclopropane-1-carboxylicacid (ACC) content. An increase in the levels of indole-3-acetic acid (IAA) and trans-Zeatin Riboside (tZR), and a reduction in the levels of gibberellin A3 (GA3) content were also observed. With the modulation of endogenous hormones, ethephon promoted female flower development, decreased plant height, thickened epicotyls, and inhibited root elongation. Hormonal biosynthesis and signal network were monitored by high-throughput sequencing. The results indicated that several key genes, including HMT3, ACS1, ACO1, EIN3, and ERFs which saw an increase in expression, were involved in ethylene biosynthesis and signal transduction. Additionally, we determined that the strongly upregulated ACO1, ERFs, and a novel AGL1 gene are likely to play an important role in female flower development. Furthermore, increased IAA content was evaluated for synthesis in the indole-3-acetaldoxime (IAOx) pathway, mediated by an upregulated UGT74B1 gene. The pathway of tZR generation was inhibited by CYP735A and CKX. We hypothesize that the increased tZR in leaves is transported from the root, where tZR is mainly produced, through a novel feedback mechanism induced by the suppressed biosynthesis pathway. It is likely that the decreased levels of GAs were caused by the action of EIN3 and ERFs through tight crosstalk between ethylene and the GAs, or by other genetic regulators such as P450 CYP736A12. This study revealed the essential ethephon response mechanism in bitter gourds and provided a framework and genetic resources for further research.

Characterization of cucumber mosaic virus (CMV) subgroup IB infecting chilli in Tamil Nadu, India.

CMV (cucumber mosaic virus) is the most primitive virus infecting chilli (Capsicum annuum. L). The mosaic incidence with leaf filiformity, mosaic mottling and stunted growth was observed in major chilli growing regions of Tamil Nadu. CMV sap was inoculated on chilli, cowpea, bitter gourd, bottle gourd, ridge gourd, banana, cucumber, Nicotiana and Chenopodium plants. Host range studies revealed that CMV produced localized infection on Nicotiana and systemic symptoms on most of the test plants. The occurrence of CMV was confirmed through DAC-ELISA and RT-PCR analysis. Host plant samples tested with DAC-ELISA showed strong reaction with 1.7 optical density. For molecular characterization, total RNA isolated from infected plants used in RT-PCR with CMV specific primers. The specific amplicons were cloned and sequenced. The complete genome sequencing depicts CMV-RNA1 consist of 3339 nucleotides (nt), RNA2 and RNA3 with 3052nt and 2027nt respectively. Phylogenetic and nucleotide sequence analysis showed TN CMV isolates closely associated with subgroup IB rather than subgroup IA and II. Comparative sequence analysis indicates replicase protein to be more variable among five genes. CP sequence analysis showed 97-98 per cent identity with subgroup IB strains, 92-93 per cent identity with subgroup IA strains and 81-82 per cent identity with subgroup II strains. CMV-RNA3 was predicted to have recombination with Indian black pepper isolate (KU947031) between 165-505nt and Egyptian tomato isolate (KX014666) between 165-506nt positions.