Characterization of cDNAs associated with lignification and their expression profiles in loquat fruit with different lignin accumulation

Abstract

The ripening fruit of two loquat (Eriobotrya japonica Lindl.) cultivars with different levels of lignin accumulation provide an intriguing example of lignification in flesh tissue. Increase in firmness as a result of lignification in ripening red-fleshed Luoyangqing (LYQ) fruit was confirmed, whereas white-fleshed Baisha (BS) fruit softened without lignification. Six cDNAs associated with the lignification pathway, i.e. EjPAL1, EjPAL2 (phenylalanine ammonia lyase, PAL, EC 4.3.1.5), Ej4CL (4-coumarate: coenzyme A ligase, 4CL, EC 6.2.1.12), EjCAD1, EjCAD2 (cinnamyl alcohol dehydrogenase, CAD, EC 1.1.1.195) and EjPOD (peroxidase, POD), were cloned from flesh tissue of LYQ fruit. Expression profiles of the six corresponding genes differed greatly in different tissues, and during fruit development and ripening in both LYQ and BS cultivars. Associated activities of PAL, 4CL, CAD, and POD enzymes were also measured. CAD and POD enzyme activities and the expression of EjCAD1 and EjPOD genes were most closely associated temporally with lignification of loquat flesh tissue. Levels of EjCAD1 transcripts were particularly aligned with changes in lignification during ripening as modified either by ethylene treatment or low temperature conditioning. The two PAL genes showed different expression patterns during fruit development, with EjPAL1 strongly expressed in mature fruit and EjPAL2 only expressed in early stages of development. In addition, EjCAD1 expression was stimulated by low temperature and may contribute to low temperature injury in the fruit. Our integrated data on lignin, monolignol precursors, and associated enzymes and genes, provide a consistent model of fruit lignification.

Coordinated regulation of anthocyanin biosynthesis in Chinese bayberry (Myrica rubra) fruit by a R2R3 MYB transcription factor

“…Total RNA was extracted using a modified CTAB method (Shan et al 2008). After removal of genomic DNA by DNase I, the concentration of total RNA was measured, and first-strand cDNA was synthesized using Revert Aid TM First Strand cDNA Synthesis kit (Fermentas, USA) according to the manufacturer's instructions.…”

Screening Quality Evaluation Factors of Freeze-Dried Peach (Prunus PersicaL. Batsch) Powders from Different Ripening Time Cultivars

“…Furthermore, the HCEL and CEL contents of late-maturing cultivars were greater than those of the early-and midmaturing cultivars except for BRF. There might be more severe lignification for the late-maturing cultivars [32].…”

Regulation of gibberellin on gene expressions related with the lignin biosynthesis in ‘Wangkumbae’ pear (Pyrus pyrifolia Nakai) fruit

“…Two CAD genes were isolated in loquat fruit, of which EjCAD1 was sensitive to ethylene and low-temperature conditions. The EjCAD1 transcript level were particularly aligned with changes in lignification, indicating a role in ripening of loquat fruit (Shan et al 2008). GbCAD1 in Ginkgo biloba played a role in the resistance mechanism to biotic and abiotic stresses as well as in tissue-specific developmental lignification (Cheng et al 2013).…”

“…The four enzymes were as following: (1) phenylalanine ammonia lyase (PAL) catalyzing the deamination of L-phenylalanine to cinnamic acid, the first step of the phenylpropanoid pathway; (2) 4-coumarate:coenzyme A ligase (4CL) catalyzing the conversion of cinnamic acid derivatives to their corresponding coenzyme A (Co A) esters; (3) cinnamyl alcohol dehydrogenase (CAD) catalyzing monolignol dehydrogenation and the last step of biosynthesis; and (4) peroxidase (POD) involved in monolignol polymerization. Currently, four genes encoding PAL are identified in Arabidopsis thaliana (Cochrane et al 2004) and parsley (Petroselinum crispum) (Logemann et al 1995), and two genes are isolated in loquat fruit (Shan et al 2008). Antisense suppression of PAL activity in tobacco leads to reductions in lignin content, as well as alterations of lignin subunit composition (Bate et al 1994;Korth et al 2001;Sewalt et al 1997).…”