Effects of Aminoethoxyvinylglycine (AVG) and 1-Methylcyclopropene (1-MCP) on the Pre-Harvest Drop Rate, Fruit Quality, and Stem-End Splitting in ‘Gala’ Apples

Preharvest fruit drop is a significant physiological problem that affects numerous commercially significant apple varieties, including ‘Gala.’ AVG and 1-MCP are two plant growth regulators commonly used to reduce fruit drop by reducing ethylene synthesis and perception, respectively. To optimize yield and market acceptance, a complete investigation of AVG and 1-MCP impacts on fruit drop and fruit quality of ‘Gala’ apples is required. In this study, four trials were conducted over the course of three years to determine the effects of AVG and 1-MCP on fruit drop and quality at harvest and after cold storage. Our results indicated that applications of AVG at the full-rate (130 mgL−1) three weeks before harvest (WBAH) were more effective at minimizing fruit drop than applications at the half-rate (65 mgL−1) and did not differ significantly from the double rate (260 mgL−1). Additionally, a single application of AVG was as effective in preventing fruit drop as two applications of 1-MCP. We also demonstrated that AVG decreased fruit skin pigmentation when used alone or in conjunction with GA4+7 or 1-MCP, while 1-MCP applications had no negative effect on fruit color. Finally, our data showed that when compared to 1-MCP and GA4+7, AVG alone was more effective in preventing stem-end splitting in Gala apples

Effects of Aminoethoxyvinylglycine (AVG) and 1-Methylcyclopropene (1-MCP) on the Pre-Harvest Drop Rate, Fruit Quality, and Stem-End Splitting in ‘Gala’ Apples

Preharvest fruit drop is a significant physiological problem that affects numerous commercially significant apple varieties, including ‘Gala.’ AVG and 1-MCP are two plant growth regulators commonly used to reduce fruit drop by reducing ethylene synthesis and perception, respectively. To optimize yield and market acceptance, a complete investigation of AVG and 1-MCP impacts on fruit drop and fruit quality of ‘Gala’ apples is required. In this study, four trials were conducted over the course of three years to determine the effects of AVG and 1-MCP on fruit drop and quality at harvest and after cold storage. Our results indicated that applications of AVG at the full-rate (130 mgL−1) three weeks before harvest (WBAH) were more effective at minimizing fruit drop than applications at the half-rate (65 mgL−1) and did not differ significantly from the double rate (260 mgL−1). Additionally, a single application of AVG was as effective in preventing fruit drop as two applications of 1-MCP. We also demonstrated that AVG decreased fruit skin pigmentation when used alone or in conjunction with GA4+7 or 1-MCP, while 1-MCP applications had no negative effect on fruit color. Finally, our data showed that when compared to 1-MCP and GA4+7, AVG alone was more effective in preventing stem-end splitting in Gala apples

Ethnomedicinal plants used by the Nag clan of the Rai Ghatual tribe of Moulvibazar district, Bangladesh

Context: Medicinal practices of the tribes of Bangladesh remain largely un-documented. Aims: The aim of the present study was to conduct an ethnomedicinal survey and documentation among the Nag clan of the Rai Ghatual tribe of Bangladesh. Settings and Design: The survey was carried out among the Nag clan of the Rai Ghatual tribal community of Moulvibazar district. The clan, according to them, is the only Nag clan of the Rai Ghatual tribe in Bangladesh. The clan has three tribal healers, still continuing their traditional medicinal practices. Materials and Methods: Interviews of the healers were carried out with the help of a semi-structured questionnaire and the guided field-walk method. Results: The Nag clan healers were observed to use 28 different plant species distributed into 22 families for treatment of ailments such as fever, loss of appetite, male infertility, dysentery, lower abdominal pain during menstruation, jaundice, stomachache, burning sensations during urination, bodily pain and weak health. Conclusions: This is the first reported study of the traditional medicinal practices of Nag clan healers. Several of the plants can be validated in their uses on the basis of existing scientific literature. The medicinal plants used by the Nag healers warrant further scientific studies, for the plants are readily available and can form alternative medicinal sources instead of costlier biomedical drugs

Ethnomedicinal plants of the Bauri tribal community of Moulvibazar District, Bangladesh

Context: Bangladesh reportedly has more than 100 tribal communities; however, documentation of their medicinal practices is markedly absent. Aim: The aim of the present study was to conduct an ethnomedicinal survey among the little known Bauri tribe of Bangladesh, whose tribal medicinal practices are yet to be documented. Settings and Design: The survey was carried out among the Bauri tribal community of Purbo Tila village in Moulvibazar District. The community is believed to be the only Bauri community in the country and had four tribal healers who continue their traditional medicinal practices. Materials and Methods: Interviews of the healers were carried out with the help of a semi-structured questionnaire and the guided field-walk method where the healers took the interviewers on guided field-walks through areas from where they collected their medicinal plants. Here they identified the plants and described their uses. Results: The Bauri healers were observed to use 40 different plant species and one bird species for treatment of ailments such as fever, respiratory tract disorders, pain, gastrointestinal disorders, eye problems like cataract and conjunctivitis, jaundice, abscess, cardiovascular disorders, urinary problems, paralysis, dog bite, snake bite, helminthiasis, lesions on the tongue or lips and piles. Leaves were the major plant part used and constituted 38.3% of total uses followed by fruits at 14.9%. Conclusions: A review of the relevant scientific literature showed that a number of medicinal plants used by the Bauri healers possess pharmacological activities, which were in line with the traditional uses, thus validating their use by the Bauri tribe

Fall Applications of Ethephon Modulates Gene Networks Controlling Bud Development during Dormancy in Peach (Prunus Persica)

Ethephon (ET) is an ethylene-releasing plant growth regulator (PGR) that can delay the bloom time in Prunus, thus reducing the risk of spring frost, which is exacerbated by global climate change. However, the adoption of ET is hindered by its detrimental effects on tree health. Little knowledge is available regarding the mechanism of how ET shifts dormancy and flowering phenology in peach. This study aimed to further characterize the dormancy regulation network at the transcriptional level by profiling the gene expression of dormant peach buds from ET-treated and untreated trees using RNA-Seq data. The results revealed that ET triggered stress responses during endodormancy, delaying biological processes related to cell division and intercellular transportation, which are essential for the floral organ development. During ecodormancy, ET mainly impeded pathways related to antioxidants and cell wall formation, both of which are closely associated with dormancy release and budburst. In contrast, the expression of dormancy-associated MADS (DAM) genes remained relatively unaffected by ET, suggesting their conserved nature. The findings of this study signify the importance of floral organogenesis during dormancy and shed light on several key processes that are subject to the influence of ET, therefore opening up new avenues for the development of effective strategies to mitigate frost risks

Contrasting bloom dates in two apple cultivars linked to differential levels of phytohormones and heat requirements during ecodormancy

10.1016/j.scienta.2021.110413SCIENTIA HORTICULTURAE28

Ethylene-Mediated Modulation of Bud Phenology, Cold Hardiness, and Hormone Biosynthesis in Peach (Prunus persica)

Spring frosts exacerbated by global climate change have become a constant threat to temperate fruit production. Delaying the bloom date by plant growth regulators (PGRs) has been proposed as a practical frost avoidance strategy. Ethephon is an ethylene-releasing PGR found to delay bloom in several fruit species, yet its use is often coupled with harmful effects, limiting its applicability in commercial tree fruit production. Little information is available regarding the mechanisms by which ethephon influences blooming and bud dormancy. This study investigated the effects of fall-applied ethephon on bud phenology, cold hardiness, and hormonal balance throughout the bud dormancy cycle in peach. Our findings concluded that ethephon could alter several significant aspects of peach bud physiology, including accelerated leaf fall, extended chilling accumulation period, increased heat requirements, improved cold hardiness, and delayed bloom date. Ethephon effects on these traits were primarily dependent on its concentration and application timing, with a high concentration (500 ppm) and an early application timing (10% leaf fall) being the most effective. Endogenous ethylene levels were induced significantly in the buds when ethephon was applied at 10% versus 90% leaf fall, indicating that leaves are essential for ethephon uptake. The hormonal analysis of buds at regular intervals of chilling hours (CH) and growing degree hours (GDH) also indicated that ethephon might exert its effects through an abscisic acid (ABA)-independent way in dormant buds. Instead, our data signifies the role of jasmonic acid (JA) in mediating budburst and bloom in peach, which also appears to be influenced by ethephon treatment. Overall, this research presents a new perspective in interpreting horticultural traits in the light of biochemical and molecular data and sheds light on the potential role of JA in bud dormancy, which deserves further attention in future studies that aim at mitigating spring frosts

Ethylene-Mediated Modulation of Bud Phenology, Cold Hardiness, and Hormone Biosynthesis in Peach (Prunus persica)

10.3390/plants10071266PLANTS-BASEL10

Label-Free Quantitative Proteomics Analysis in Susceptible and Resistant Brassica napus Cultivars Infected with Xanthomonas campestris pv. campestris

Black rot, caused by Xanthomonas campestris pv. campestris (Xcc), is the main disease of cruciferous vegetables. To characterize the resistance mechanism in the Brassica napus–Xcc pathosystem, Xcc-responsive proteins in susceptible (cv. Mosa) and resistant (cv. Capitol) cultivars were investigated using gel-free quantitative proteomics and analysis of gene expression. This allowed us to identify 158 and 163 differentially expressed proteins following Xcc infection in cv. Mosa and cv. Capitol, respectively, and to classify them into five major categories including antioxidative systems, proteolysis, photosynthesis, redox, and innate immunity. All proteins involved in protein degradation such as the protease complex, proteasome subunits, and ATP-dependent Clp protease proteolytic subunits, were upregulated only in cv. Mosa, in which higher hydrogen peroxide accumulation concurred with upregulated superoxide dismutase. In cv. Capitol, photosystem II (PS II)-related proteins were downregulated (excepting PS II 22 kDa), whereas the PS I proteins, ATP synthase, and ferredoxin-NADP+ reductase, were upregulated. For redox-related proteins, upregulation of thioredoxin, 2-cys peroxiredoxin, and glutathione S-transferase occurred in cv. Capitol, consistent with higher NADH-, ascorbate-, and glutathione-based reducing potential, whereas the proteins involved in the C2 oxidative cycle and glycolysis were highly activated in cv. Mosa. Most innate immunity-related proteins, including zinc finger domain (ZFD)-containing protein, glycine-rich RNA-binding protein (GRP) and mitochondrial outer membrane porin, were highly enhanced in cv. Capitol, concomitant with enhanced expression of ZFD and GRP genes. Distinguishable differences in the protein profile between the two cultivars deserves higher importance for breeding programs and understanding of disease resistance in the B. napus–Xcc pathosystem

Cultivar Variation in Hormonal Balance Is a Significant Determinant of Disease Susceptibility to Xanthomonas campestris pv. campestris in Brassica napus

This study aimed to directly elucidate cultivar variation in disease susceptibility and disease responses in relation to hormonal status in the interaction of Brassica napus cultivars and Xanthomonas campestris pv. campestris (Xcc), the causal agent of black rot disease. Fully expanded leaves of six B. napus cultivars (cvs. Capitol, Youngsan, Saturnin, Colosse, Tamra, and Mosa) were inoculated with Xcc. At 14 days post-inoculation with Xcc, cultivar variation in susceptibility or resistance was interpreted with defense responses as estimated by redox status, defensive metabolites, and expression of phenylpropanoid synthesis-related genes in relation to endogenous hormonal status. Disease susceptibility of six cultivars was distinguished by necrotic lesions in the Xcc-inoculated leaves and characterized concurrently based on the higher increase in reactive oxygen species and lipid peroxidation. Among these cultivars, as the susceptibility was higher, the ratios of abscisic acid (ABA)/jasmonic acid (JA) and salicylic acid (SA)/JA tended to increase with enhanced expression of SA signaling regulatory gene NPR1 and transcriptional factor TGA1 and antagonistic suppression of JA-regulated gene PDF 1.2. In the resistant cultivar (cv. Capitol), accumulation of defensive metabolites with enhanced expression of genes involved in flavonoids (chalcone synthase), proanthocyanidins (anthocyanidin reductase), and hydroxycinnamic acids (ferulate-5-hydroxylase) biosynthesis and higher redox status were observed, whereas the opposite results were obtained for susceptible cultivars (cvs. Mosa and Tamra). These results clearly indicate that cultivar variation in susceptibility to infection by Xcc was determined by enhanced alteration of the SA/JA ratio, as a negative regulator of redox status and phenylpropanoid synthesis in the Brasica napus–Xcc pathosystem