Fruit cracking is a common physiological disease. Many fruits such as tomato, sweet cherry, apple, jujube, pomegranate, and litchi are liable to crack, causing considerable economic loss and agricultural resources waste. The mechanisms of fruit cracking are comprehensive. Some correlations have been observed between susceptibility of fruit cracking and some fruit traits (genetic, fruit size, fruit shape, fruit growth rate, water content, fruit skin characteristics, related gene expression, etc). Also, environmental condition (temperature, light, rainfall, etc) and orchard management (irrigation, sun-shade, mineral, growth regulator, etc) can influence fruit cracking. Here, progress in studies on fruit cracking is reviewed to provide a reference for prevention and control of fruit cracking.
Fruit ; Litchi ; Lycopersicon esculentum

The environmental gas concentration affects the storage period and quality of fruits and vegetables. High concentration CO₂ treating for a long time will cause damage to fruits, However, the specific molecular mechanism is unclear. To analyze the mechanism of CO₂ injury in apple, high-throughput sequencing technology of Illumina Hiseq 4000 and non-targeted metabolism technology were used to analyze the transcriptome sequencing and metabolomics analysis of browning flesh tissue of damage fruit and normal pulp tissue of the control group. A total of 6 332 differentially expressed genes were obtained, including 4 187 up-regulated genes and 2 145 down regulated genes. Functional analysis of the differentially expressed genes confirmed that the occurrence of CO₂ injury in apple was related to redox process, lipid metabolism, hormone signal transduction process and energy metabolism process. Twenty candidate browning genes were successfully screened, among which grxcr1 (md14g1137800) and gpx (md06g1081300) participated in the reactive oxygen species scavenging process, and pld1_ 2 (md15g1125000) and plcd (md07g1221900) participated in phospholipid acid synthesis and affected membrane metabolism. mdh1 (md05g1238800) participated in TCA cycle and affected energy metabolism. A total of 77 differential metabolites were obtained by metabolomic analysis, mainly organic acids, lipids, sugars and polyketones, including 35 metabolites related to browning. The metabolism of flavonoids was involved in the browning process of apple. Compared with the control tissue, the content of flavonoids such as catechin and quercetin decreased significantly in the damaged apple tissue, the antioxidant capacity of cells decreased, the redox state was unbalanced, and the cell structure was destroyed, resulting in browning. The results of this study further enrich the theoretical basis of CO₂ damage, and provide reference for the practical application of high concentration CO₂ preservation technology.
Carbon Dioxide ; Fruit ; Gene Expression Regulation, Plant ; Malus/genetics* ; Metabolome ; Transcriptome