Isolation and Identification of Anthracnose Pathogen from Fruit of Red Fuji Apple

The fruits of Red Fuji apple with anthracnose symptoms were collected and submitted to tissue isolation and culture. One strain of anthracnose pathogen （numbered as Acgl） was obtained, and it was identified by both morphological and molecular biological methods. According to the morphological characteristics of the colony and conidia and the results of rDNA-ITS sequence analysis, the Acgl strain was identified as Colletotrichum gloeosporioides.

Detection of Chlorpyrifos Residues in Akesu Red Fuji Apple based on Near Infrared Spectrum

[Objective] The paper was to explore a method for detecting chlorpyrifos residues in red Fuji apple. [Method] The original spectral data of apple samples sprayed with different volume fractions of chlorpyrifos were collected using near infrared spectrometer at the band of 4 000-10 000 cm^（-1）. The original spectra were pre-treated by a variety of methods, and partial least squares（PLS） model was established for predictive analysis. [Result] Near infrared spectrum showed sensitivity to apple samples sprayed with different volume fractions of chlorpyrifos, but had low precision on pesticide-free samples. Data of blank control group were further eliminated for modeling prediction. The results showed that the results were the best when pre-treated with first derivative（FD）： R=0.987 9; the square error of prediction（SEP） was 0.173 6; the root-mean-square error of cross-validation（RMSECV） was 0.120 5; and the precision was 0.923 4. [Conclusion] Near infrared spectrum can better predict chlorpyrifos residue, providing a new method for detecting chlorpyrifos residues in Akesu red Fuji apple.

Effects of 1-methylcyclopropene treatment on the quality of red‘Fuji’apples fruit during short-term storage

Objectives:The aim of this study is to determine the mechanism through which 1-methylcyclopropene(1-MCP)affects the quality of red'Fuji'apples,which were stored for a short duration.Materials and Methods:Red‘Fuji’apples were treated with 1-MCP(1.0μl/L),stored at 25℃for0,12,24,48,72,and 96 h,and ethylene pro-duction was measured.An integrated metabolomic and transcriptomic analysis was performed on apples stored for 24 h.Results:The release of ethylene was significantly delayed from red‘Fuji’apples subjected to 1-MCP treatment.By performing an integrated transcriptome and metabolome analyses,we identified 117 differentially expressed genes(DEGs)and 44 differentially accumulated metabol-ites(DAMs).By performing functional enrichment analysis,we found that DEGs were involved in the following pathways;carbon metabolism(LPD2,gpmA,LTA2,ACC,PSAT1,MdCAS2),phytohormone signal transduction(EBF 7),amino acid metabolism(MdACS-1),fatty acid metab-olism(LOX1.5,KCS4,KAST),energy metabolism(Lhcb1,Lhcb6,PsbY,GPDHC1,PUMP5I,metabolic pathways(TRE1,HEXO1)and cell wall metabolism(CSLG2).Thus,these DEGs were involved in the ripening of fruits,and they controlled the quality of fruits at the post-harvest stage.The metabolites were enriched with DAMs.These were found to be individually involved in the metabolic pathway,secondary metabolite bio-synthesis,phenylpropanoid biosynthesis,flavonoids,and flavonol synthesis.Conclusions:The results indicate that 1-MCP inhibits the biosynthesis of ethylene and suppresses energy metabolism.Moreover,it also downregulates metabolic pathways and the enzymatic genes related to fruit quality.Therefore,1-MCP delays the ripening of fruits at the post-harvest stage.This study helps us understand how 1-MCP treatment affects the ripening and quality of fruits.