Incidence Characteristics And Molecule Mechanism Of Surface Dot Piting Of ’Lingwu Long’ Jujube During Storage

LingWu long jujube is a kind of local characteristics fruit in Ningxia, acreage of which has more than33000acres.The preservation technology is the bottleneck of industrial development of LingWu long jujube.As the jujube fruit is easy to ferment, so its preservation technology has become a world technology challenges.The storage Techniques of the jujube directly affects the income of Zaonong, so new technology of storage need development and promotion.When we study about the preservation technology of Lingwu long jujube, we found that Lingwu long jujube often suffer from a disease which performance concave spot in the cold storage.This disease seriously affect the value of the goods Lingwu long jujube,which severe high as30%to40%. This disease is initially identified a physiological disease that occur during low temperature storage as a low-temperature stress with the recessed spot symptoms, but the pathology and the etiology is uncertain. To be able to find a balance between cryogenic preservation and the prevention of surface dot piting, our group have a preliminary study about the surface dot piting of Lingwu long jujube. We studied the symptoms and physiological characteristics of Lingwu long jujube surface dot piting, and studied the changes of activity of the phenylalanine ammonia lyase (PAL) during the onset of surface dot piting which is cold stress-related. Also we studied on the transcriptome level, analyzed and studied the metabolic pathways and GO terms of Lingwuchangzao which is associated the surface dot piting. Experimental results are as follows:1. The recessed spot symptoms began to appear after the pre-cooling or cold storage7-10days, disease site and lesion size is irregular, and the shape is irregular semi-spherical. The lesion flesh is spongy and browning, but no rot or lees flavor. Through literature review, we stored Lingwu long jujube in different storage conditions and found that the incidence is associated with the storage temperature.So the initial diagnosis of the disease is low stress damage.2. The content of Zn in the incidence fruit tissue is less than healthy fruit tissue, but the content of Ca and Fe are both higher than in healthy fruit; the activity of the polyphenol oxidase and the phenylalanine ammonia lyase in disease fruit were higher than in healthy fruit, and the difference was significant; relative to the peel of the healthy fruit, the microstructure of the epidermal tissue of the lesion site is uneven and rough,which can show large areas of uniform crack band, and the flesh tissue is messy, with varying degrees of wrinkles, looser organization, or seriously damaged.3. Phenylalanine ammonia lyase is a plant enzyme associated with anti-stress, according to the study results suggested that in the process of surface dot piting PAL gene expression changes occurring should be as follow:in the low temperature stress, the expression of PAL rose, and the concave spot symptoms appear at the surface of the fruit, then with the continued serious disease severity, the overall activity of pulp cells decline, so the expression of PAL tends to decrease too.4. By enrichment analysis about GO item and metabolic pathway, we found that the occurrence of surface dot piting associated with the environmental adaptation metabolic pathway; due to the occurrence of surface dot piting accompanied with the expression changes of genes about the signal transduction,transport and catabolic metabolic pathway, so we can predict that through the development of molecular diagnostic techniques can predict the occurrence of surface dot piting; the relevance between the surface dot piting and the metabolic pathway such as folding, sorting,degradation, translation and transformation is also high, indicating that the regulation of surface dot piting exists on transcription level.