Genome-Wide Identification of Laccase Gene Family from Punica granatum and Functional Analysis towards Potential Involvement in Lignin Biosynthesis

Abstract

Laccase (LAC) is the key enzyme responsible for lignin biosynthesis. Here, 57 PgLACs from pomegranate were identified and distributed on eight chromosomes and one unplaced scaffold. They were divided into six groups containing three typical Cu-oxidase domains. Totally, 51 cis-acting elements in the promoter region of PgLACs are involved in response to ABA, GA, light, stress, etc., indicating diverse functions of PgLACs. The expression profiles of 13 PgLACs during the seed development stage showed that most PgLACs expressed at a higher level earlier than at the later seed development stage in two pomegranate cultivars except PgLAC4. Also, PgLAC1/6/7/16 expressed at a significantly higher level in soft-seed ‘Tunisia’; on the contrary, PgLAC37 and PgLAC50 with a significantly higher expression in hard-seed ‘Taishanhong’. Combined with their distinguishing cis-acting elements, it was concluded that PgLAC1/6/7 may respond to GA via TATC-box and GARE-motif, and PgLAC16 repressed the promotor activity of embryo mid-maturation genes via RY-element so as to contribute to softer seed formation, whereas PgLAC37/50 may participate in seed formation and accelerate seed maturity via ABRE and G-box elements. Collectively, the dramatic gene expressions of PgLAC1/6/7/16/37/50 will provide valuable information to explore the formation of soft- and hard-seed in pomegranate.

Identification of Laccase Genes in Grapevine and Their Roles in Response to Botrytis cinerea

“…pekinensis (27) [49], Brassica rapa var. rapa (27) [49], Bretschneideri (45) [25], Citrus sinensis (41) [41] and Punica granatum (57) [43] have been revealed. Comparatively, Triticum aestivum (95) [50], soybean (93) and Gossypium hirsutum (84) [28] have more LAC members.…”

“…Each leaf sample collected at the indicated time points was dried at 80 • C to constant weight, ground to powder, and sieved with a 0.425 mm aperture sieve. Then, 2 mg samples were evaluated in terms of lignin content (expressed as mg g −1 ) by using the MZS-1-G Kit (Suzhou Comin Biotechnology Co. Ltd., Suzhou, Jiangsu, China) [43]. Then, homogenates made with 0.1 g samples with 1 mL of extracting solution in an ice bath were centrifuged at 1200 g at 4 • C for 30 min to obtain supernatant liquid.…”

Contribution of the LAC Genes in Fruit Quality Attributes of the Fruit-Bearing Plants: A Comprehensive Review

“…In fruits, lignification is involved in the development of the fruit's texture and resistance to mechanical stress and pathogens [3]. The LAC gene family, which encodes laccase enzymes, is known to be involved in lignin biosynthesis in plants [2]. Lignin biosynthesis begins with the synthesis of phenylpropanoids, which are then polymerized into lignin [2].…”

“…The LAC gene family, which encodes laccase enzymes, is known to be involved in lignin biosynthesis in plants [2]. Lignin biosynthesis begins with the synthesis of phenylpropanoids, which are then polymerized into lignin [2]. One of the key steps in this process is the oxidation of monolignols, which are the monomeric building blocks of lignin.…”

“…The LAC (Laccase) genes encode an enzyme called laccase, which is involved in lignin biosynthesis and oxidative reactions in plants [1,2]. Lignin is a complex polymer that makes up the cell walls of many plants and is responsible for their strength and rigidity [1,3].…”