By analyzing the curd texture trait data of loose-curd cauliflower germplasm resources, a unified and objective evaluation method for loose-curd cauliflower curd texture was established. The potential factors affecting curd texture were also studied to provide references for the evaluation of loose-curd cauliflower edible quality and quality breeding.

Texture Profile Analysis (TPA) and sensory evaluation method were used to evaluate 166 loose-curd cauliflower germplasm resources. Data of 5 TPA indicators (hardness, cohesiveness, springiness, chewiness, resilience) and 3 sensory evaluation indicators (sensory crispness, sensory hardness, sensory chewiness) were obtained. Correlation analysis and linear regression analysis were carried out to construct the relationship model between sensory evaluation indicators and texture parameters. Through principal component analysis, membership function analysis and cluster analysis, a mathematical model for loose-curd cauliflower curd texture evaluation was established, and the texture groups of loose-curd cauliflower germplasm resources were divided. Furthermore, the differences in cell microstructure and cell wall component contents of loose-curd cauliflower curds among different groups were analyzed to explore the potential factors affecting loose-curd cauliflower curd texture.

Significant differences were observed in eight curd texture indicators among different loose-curd cauliflower germplasms, with chewiness showing the greatest degree of dispersion. Sensory evaluation indicators were positively correlated with TPA indicators to varying extents. By establishing linear regression equations between them, it was found that hardness has important predictive value in sensory texture evaluation. Principal Component Analysis (PCA) extracted two principal components affecting loose-curd cauliflower curd texture, with a cumulative contribution rate of 90.22%. Among them, the first principal component mainly includes hardness, chewiness, and springiness, which are key parameters determining the palatability of loose-curd cauliflower. A mathematical model for evaluating loose-curd cauliflower curd texture was established: Comprehensive texture score C=-2.045+0.017×chewiness+3.108×resilience+0.555×springiness+0.010×hardness+1.950×cohesiveness. Based on the C values, 166 loose-curd cauliflower germplasms were classified into three groups. GroupⅠ had the lowest C values(0.01≤C≤0.35), characterized by low hardness and poor chewiness, and was classified as the soft type; GroupⅡ had moderate C values (0.37≤C≤0.62), with balanced texture and good palatability, and was classified as the crisp-tender type; GroupⅢhad the highest C values (0.65≤C≤1.00), exhibiting high hardness and chewiness, and was classified as the crisp-springy type. Significant differences in cell structure and cell wall components were detected among cauliflower florets of different textures. The crisp-springy type featured florets with high cell roundness, compact structure, and high contents of cellulose and hemicellulose; the crisp-tender type had florets with plump and uniformly structured cells, and an appropriate ratio of cellulose, hemicellulose, and soluble pectin contents; the soft type displayed florets with obvious cell gaps and loose structure, along with a higher soluble pectin content.

A mathematical model for loose-curd cauliflower curd texture evaluation was established: C=-2.045+0.017×chewiness+3.108×resilience+0.555×springiness+0.010×hardness+1.950×cohesiveness. The C value ranges dividing different loose-curd cauliflower curd texture types can be used for the identification of loose-curd cauliflower germplasm resources. It was also found that cell structure and cell wall components have important effects on the texture quality of loose-curd cauliflower curds.

The aim of this study was to identify the co expression modules of luffa fruit length and diameter development and to screen key regulatory genes, so as to provide the theoretical basis for subsequent research on the molecular mechanism of fruit shape control in luffa.

The luffa fruits in 9 fruit development stages (2 days before anthesis, and 0, 2, 4, 6, 8, 10, 15, and 20 days after anthesis) were applied as research materials. The fruit length and diameter of each stage were measured. The WGCNA method was used to jointly analyze transcriptome and fruit length and diameter data, to identify co-expressed gene modules of fruit length and diameter development, and to screen out key regulatory genes.

A total of 14 co expression modules were identified by WGCNA, among which two modules (Turquoise and Lightpink4) were significantly correlated with fruit length and diameter (absolute value of correlation coefficient=0.9); Turquoise module was significantly positively correlated, while Lightpink4 module was significantly negatively correlated. KEGG enrichment analysis found that the Turquoise module was significantly enriched in endocytosis and phenylpropanoid biosynthesis pathways, which were closely related to fruit enlargement and growth regulation, and could be used as a key gene module for studying fruit length and diameter in luffa. According to the connectivity and functional annotation of genes in Turquoise module, ten key regulatory genes were screened, including xyloglucan endotransglucosylase/hydrolase gene XTH23, actin-depolymerizing factor gene ADF2, chaperone protein gene DnaJ10, expansin gene (EXPA1, EXPA4 and EXLA5), kinesin gene kinesin-13A, auxin response genes SAUR21, and Aux/IAA11. The RT-qPCR results showed that the expression levels of ten regulatory genes significantly increased after the fruit entered the rapid growth period (8 day after anthesis), with an increase of 2-50 times approximately. Through constructing a gene interaction network, it was found that some candidate genes interacted with the WRKY, bHLH, and HSF transcription factor families.

The Turquoise module, an important co expression module of luffa fruit length and diameter was obtained, and ten potential candidate genes for luffa fruit shape control were screened. It was found that luffa fruit length and diameter development regulation mainly involved the processes of cell wall reconstruction, cell development and differentiation, and auxin regulation.