Revealing the Specific Regulations of Brassinolide on Tomato Fruit Chilling Injury by Integrated Multi-Omics

Tomato fruit is susceptible to chilling injury (CI) when stored at low temperatures, limiting its storage potential, and resulting in economic loss if inappropriate temperatures are used. Brassinolide (BR) is a plant growth regulator that is known to decrease the susceptibility of fruit to CI. In this study, transcriptome, metabolome, and proteome analysis revealed the regulation mechanism of BR treatment in alleviating tomato fruit CI. The results showed that the differentially expressed metabolites mainly included amino acids, organic acids, carbohydrates, and lipids. Differentially expressed genes (DEGs) were involved in plant cold stress response (HSFA3, SHSP, and TPR), fruit redox process (POD, PAL, and LOX), related to the fruit texture (CESA, β-Gal, and PAE), plant hormone signal transduction (ACS3, ARF, and ERF,), transcription factors (TCP, bHLH, GATA). Moreover, differentially expressed proteins were associated with fruit texture (CESA, PE, PL, and CHI), plant oxidation processes (LOX, GPX, CAT, and POD), plant cold stress response (HSF, HSP20, HSP70, and HSP90B), plant hormone signal transduction (BSK1 and JAR1) and transcription factors (WRKY and MYB). Our study showed that BR alleviates CI symptoms of tomato fruit by regulating LOX in the α-linolenic acid metabolism pathway, enhancing jasmonic acid-CoA (JA-CoA) synthesis, inhibiting cell wall and membrane lipid damage. The results provided a theoretical basis for further study on the CI mechanism of tomato fruit.

The genus Salacia (Celastraceae: Salaciodeae) in peninsular India

The genus Salacia (Celastraceae: Salaciodeae) in peninsular India is revised, wherein ten species are recognised. Eight species are endemic to the region. Salacia macrophylla and S. reticulata are excluded from the revision as occurrence of both the species is doubtful in mainland India. Salacia macrosperma exhibits great variation in leaf shape, flower number, pedicel length and fruit texture, hence the morphologically similar species S. beddomei and S. vellaniana are relegated to its synonymy. Descriptions, photographs, and pen and ink as well as colour drawings of all recognised Salacia species are provided with an artificial key, updated nomenclature, and synonymy. Distribution and IUCN Red list categories and criteria are also discussed. Seven binomials, S. fruticosa, S. macrophylla, S. macrosperma, S. oblonga, S. ovalis, Tontelea prinoides and Johnia coromadeliana are lectotypified.

Quantitative trait locus analysis of cucumber fruit texture using double-digest restriction-site-associated DNA sequencing

Fruit firmness and crispness are important traits of cucumber because they directly affect its commercial value. We performed quantitative trait locus (QTL) analysis of these fruit texture traits with the double-digest restriction-site-associated DNA sequencing (ddRAD-Seq) technique and detected 31 QTLs for fruit firmness: 11 for placenta firmness, 12 for skin firmness, and 8 for flesh firmness; and 25 QTLs for crispness-related scores: 10 for flesh crispness index, 8 for flesh apparent fractal dimension by Richardson plot, and 7 for flesh apparent fractal dimension by box-counting (Kolmogorov’s dimension). Several QTLs associated with flesh firmness and crispness are located near regions for fruit length, diameter, and length-to-diameter ratio, and for resistance to powdery mildew and downy mildew, indicating that gene linkage is likely to limit breeding efficiency. Our results will contribute to the development of informative DNA markers closely linked to genes for desirable fruit texture traits that are required for effective selection of new cultivars.

Dietary fiber components, microstructure, and texture of date fruits (Phoenix dactylifera, L.)

Date fruits vary widely in the hardness of their edible parts and they are classified accordingly into soft, semi-dry, and dry varieties. Fruit texture, a significant parameter in determining consumer acceptance, is related to the tissue structure and chemical composition of the fruit, mainly the ratio of sucrose to reducing sugars. This study aimed to understand the relationship between the chemical composition, microstructure, and texture profile of 10 major Emirati date fruits. The soluble sugars, glucose and fructose, represent ca 80 g/100 g of the fruits on the basis of dry weight (DW) while the dietary fiber contents varied 5.2–7.4 g/100 dg D.W. with lignin being the main determinant of the variability. The textures of the samples were studied using instrumental texture profile analysis. While no correlation was found between the soluble sugar and texture parameters in this study, the different fiber constituents correlated variably with the different parameters of date fruit texture. Lignin, arabinoxylan, galactomannan, and pectin were found to correlate significantly with fruit hardness and the related parameters, gumminess and chewiness. Both lignin and arabinoxylan correlated with resilience, and arabinoxylan exhibited a strong correlation with cohesiveness.

Eleven-year Correlation of Physical Fruit Texture Traits between Computerized Penetrometers and Sensory Assessment in an Apple Breeding Program

Fruit texture is a major target of apple (Malus domestica) breeding programs due to its influence on consumer preference. This multitrait feature is typically rated using sensory assessment, which is subjective and prone to biases. Instrumental measurements have predominantly targeted firmness of the outer region of fruit cortex using industry standard Magness–Taylor-type penetrometers, while other metrics remain largely unused. Additionally, there have been limited reports on correlating sensory attributes with instrumental metrics on many diverse apple selections. This report is the first to correlate multiyear historical fruit texture information of instrumental metrics and sensory assessment in an apple breeding program. Through 11 years of routine fruit quality evaluation at the Washington State University apple breeding program, physical textural data of 84,552 fruit acquired from computerized penetrometers were correlated with sensory assessment. Correlations among various instrumental metrics are high (0.63 ≤ r ≤ 1.00; P < 0.0001). In correlating instrumental outputs with sensory data, there is a significant correlation (r = 0.43; P < 0.0001) between the instrumental crispness value and sensory crispness. Additionally, instrumental hardness traits are significantly correlated (0.61 ≤ r ≤ 0.69; P < 0.0001) with sensory hardness. Outputs from two versions of computerized penetrometers were tested and shown to have no statistical differences. Overall, this report demonstrates potential use of instrumental metrics as firmness and crispness estimates for selecting apples of diverse backgrounds in a breeding program. However, in testing a large number and diversity of fruit, experimenters should perform data curation and account for lower limits/thresholds of the instrument.