The objectives of the current study were to isolate and identify the pathogen responsible for citrus canker and investigate the efficacy of sulfone derivatives containing 1,3,4-oxadiazole moiety on controlling citrus canker caused by Xanthomonas citri subsp. citri (Xcc) under in vitro and field conditions. In an in vitro study, we tested eight sulfone derivatives against Xcc and the results demonstrated that compound 3 exhibited the best antibacterial activity against Xcc, with a half-maximal effective concentration (EC₅₀) value of 1.23 μg/mL, which was even better than those of commercial bactericides Kocide 3000 (58.21 μg/mL) and Thiodiazole copper (77.04 μg/mL), respectively. Meanwhile, under field experiments, compound 3 treatments demonstrated the highest ability to reduce the disease of citrus canker in leaves and fruits in two different places relative to an untreated control as well as the commercial bactericides Kocide 3000 and Thiodiazole copper. Meanwhile, compound 3 could stimulate the increase in peroxidase (POD), polyphenol oxidase (PPO), and phenylalanine ammonia lyase (PAL) activities in the navel orange leaves, causing marked enhancement of plant resistance against citrus canker. Moreover, compound 3 could damage the cell membranes, destruct the biofilm formation, inhibit the production of extracellular polysaccharide (EPS), and affect the cell membrane permeability to restrain the growth of the bacteria.

As an excellent variety of Camphora glanduliferum, Honganzhang has high essential oil content and can be used as industrial and pharmaceutical raw materials to extract essential oil, which has high development value. In this study, fresh branches and leaves of C. glanduliferum ’Honganzhang’ were used as materials. After extracting C. glanduliferum ’Honganzhang’ essential oils (CGHEO) by steam distillation, gas chromatography-mass spectrometry (GC-MS) was used to analyze its chemical components. On this basis, the antibacterial effect of CGHEO and its potential physiological mechanism were further explored. The results showed that the main components of CGHEO were Cineole (46.57%), α-terpineol (9.93%), Sabinene (8.02%), β-terpinene (6.04%), and α-pinene (4.49%), these compounds can be used in medicine, food and other industries. In terms of antibacterial effect, CGHEO has significant antibacterial effects on three Gram-negative bacteria (Escherichia coli, Salmonella enteritidis, and Pseudomonas aeruginosa), and two Gram-positive bacteria (Bacillus subtilis and Staphylococcus aureus). CGHEO can reduce Na⁺K⁺-ATPase activity and SDH activity and further interfere with the operation of the bacterial respiratory chain, thereby achieving the effect of inhibiting bacterial reproduction. Based on the main chemical components contained in C. glanduliferum ’Honganzhang’ and its remarkable antibacterial effect, this study is expected to provide a theoretical basis for the wide application of C. glanduliferum ’Honganzhang’ in multiple fields such as medicine, health care, food, and industry.

Bougainvillea has large and vibrant-colored bracts, which are widely used in landscape gardening. In order to study the changing pattern of pigmentation and the expression of genes related to pigment synthesis during different developmental periods of the bracts of B. × buttiana, we determined the color parameters of the bracts of B. × buttiana has by using colorimetric color cards and colorimeters, and quantitatively determined the contents of chlorophyll a, chlorophyll b, betacyanin, betaxanthin and flavonoids, and the expression of genes related to pigment synthesis was detected during the BR1 and BR3. The results showed that the bracts of B. × buttiana ‘Miss Manila’ can be classified into four distinct growth and developmental stages, namely Bract Primordial Stage (BR1), Bract Color Transition Stage (BR2), Bract Maturation Stage (BR3), and Bract Senescence Stage (BR4). The BR1 have lower color saturation, brightness, and redness, and with bract development, their color saturation, brightness, and redness gradually increased. In addition, chlorophyll content was highest at the BR1 (2.2 mg/g), and from the BR1, flavonoids and betalain content began to increase, and higher betacyanin content in all stages, with betacyanin being the highest at the BR3 at 4.94 mg/g. Correlation analysis of the color parameters with pigment content showed that chlorophyll a, betacyanin, and flavonoid contents were significantly correlated with the bract color changes. With bract development, the betalain metabolism pathway BgDODA gene was significantly up-regulated; the flavonoid metabolism pathway BgDFRA and BgF3H genes were significantly up-regulated, whereas the BgDTX, BgFLS, and BgCHIL genes were significantly down-regulated; and the chlorophyll metabolism pathway BgSGR gene was significantly up-regulated, whereas the BgPORA gene was down-regulated in expression. ProtParam-based analysis characterized the BgFLS-encoded protein as a stable, hydrophilic 2-oxoglutarate-dependent oxidoreductase lacking transmembrane domains and a signal peptide, and the BgCHIL-encoded protein as a stable, hydrophilic chalcone isomerase also lacking transmembrane domains and a signal peptide. In summary, betalain metabolism, flavonoid metabolism and chlorophyll metabolism jointly regulate the bract color change of B. × buttiana has, and it is possible that the genes of BgCHIL, BgFLS, BgSGR, and BgF3H are involved in the regulation of the bract color change of B. × buttiana.

Genotyping and Genetic Diversity Analysis of 47 Flowering Cherry ( Cerasus ) Germplasms