The role of polyamines during exocarp formation in a russet mutant of ‘Dangshansuli’ pear (Pyrus bretschneideri Rehd.)

Abstract

Differential genes of suberin, polyamine and transcription factors in transcriptome sequences and the contents of H 2 O 2 , spermidine, spermine, and putrescine changed significantly after treating with MGBG. Russeting is a commercially important process that restores the control of water loss through the skin via the formation of a waterproofing periderm just beneath the microcracked skin of pear primary fruit. A spontaneous russet skin mutant, the yellow-green 'Dangshansuli' pear, has been identified. To understand the role of polyamines in the formation of the russet skin of the mutant-type (MT) pear, it was treated with methylglyoxal-bis-(guanylhydrazone) (MGBG) for 4 weeks after full bloom. One week later, differentially expressed genes among the wild-type (WT), MT, and MGBG-treated MT pears were screened, hydrogen peroxide (H2O2) was localized using CeCl3, and the contents of H2O2 and polyamine were measured. A total of 57,086,772, 61,240,014, and 67,919,420 successful reads were generated from the transcriptomes of WT, MT, and MGBG-treated MT, with average unigene lengths of 701, 720, and 735 bp, respectively. Differentially expressed genes involved in polyamine metabolism and suberin synthesis were screened in 'Dangshansuli' and in the mutant libraries, and their relative expression was found to be significantly altered after treatment with MGBG, which was confirmed by real-time PCR. The expression patterns of differentially expressed transcription factors were identified and were found to be similar to those of the polyamine- and suberin-related genes. The results indicated that the H2O2 generated during polyamine metabolism might contribute to russet formation on the exocarp of the mutant pear. Furthermore, the contents of H2O2, spermidine, spermine, and putrescine and H2O2 localization provided a comprehensive transcriptomic view of russet formation in the mutant pear.

Potato native and wound periderms are differently affected by down-regulation of FHT, a suberin feruloyl transferase

“…Phenolic amines can combine the growth and development regulatory functions of polyamines (Martin-Tanguy, 1985) with the toxic free radical scavenging, antioxidative, and wall-strengthening properties conferred by hydroxycinnamic acids (Volpert et al, 1995, among others). It was suggested by (Heng, et al, 2016) that the H 2 O 2 generated during polyamine metabolism might contribute to russet formation on the exocarp of pear fruits. A role as cross-linked intermediates putatively involved in the suberization process was suggested by King and Calhoun (King & Calhoun, 2005, 2010) for feruloyl amides and cross-linked dimers in potato scab lesions.…”

Lignin and Quercetin Synthesis Underlies Berry Russeting in ‘Sunshine Muscat’ Grape

“…Thus far, researchers have studied pear and apple russet in detail. Research on 'Dangshansu pear' has shown that phenylpropane metabolic pathways are related to the formation of russet, and lignin biosynthesis can regulate russet formation [8,25]. Enzymes involved in lignin biosynthesis can be divided into three categories [26]: (1) enzymes in the phenylalanine metabolic pathway, e.g., PAL and 4CL, which show expression that is closely related to the total lignin, (2) enzymes related to the regulation of lignin monomer synthesis in lignin-specific synthesis pathways, e.g., COMT and CCo AOMT, (3) enzymes downstream of the lignin synthesis branch pathway and involved in the regulation of enzymes involved in the synthesis and polymerization of lignin monomers, including CCR, CAD, and POD, which are responsible for the ultimate reduction of various hydroxycinnamyl-coenzyme A esters into lignin monomers.…”

Characterization and expression of the ABC family (G group) in ‘Dangshansuli’ pear (Pyrus bretschneideri Rehd.) and its russet mutant

“…RT-qPCR was performed with the SYBR Green PCR Master Mix (TOYOBO (SHANGHAI) BIOTECH) and carried out in an optical 48-well plate using an ABI PRISM 7300 Sequence Detection System (Applied Biosystems). The reactions and profiles were run according to the methods of Heng et al (2016) . Three independent biological replicates were performed.…”

“…The mature skin of ‘Dangshansuli’ pear is yellow-green, whereas the mutant is a russet color. To further explore the expression patterns of PbABCG family genes in ‘Dangshansuli’ and its russet mutant, ten PbABCG genes with differential expression (log 2 Ratio ≥ 1, FDR ≤ 0.001) were screened in the transcriptome of ‘Dangshansuli’ and its russet mutant ( Heng et al , 2016 ), which were validated at 25, 50, 75, 100, 125, 150, and 175 days after full bloom (DAFB) by real-time quantitative PCR (RT-qPCR), which would better reflect expression in different periods. The results will contribute to the understanding of the role of PbABCGs in the formation of suberin.…”