A Pectate Lyase Gene Plays a Critical Role in Xylem Vascular Development in Arabidopsis

Abstract

As a major component of the plant primary cell wall, structure changes in pectin may affect the formation of the secondary cell wall and lead to serious consequences on plant growth and development. Pectin-modifying enzymes including pectate lyase-like proteins (PLLs) participate in the remodeling of pectin during organogenesis, especially during fruit ripening. In this study, we used Arabidopsis as a model system to identify critical PLL genes that are of particular importance for vascular development. Four PLL genes, named AtPLL15, AtPLL16, AtPLL19, and AtPLL26, were identified for xylem-specific expression. A knock-out T-DNA mutant of AtPLL16 displayed an increased amount of pectin, soluble sugar, and acid-soluble lignin (ASL). Interestingly, the atpll16 mutant exhibited an irregular xylem phenotype, accompanied by disordered xylem ray cells and an absence of interfascicular phloem fibers. The xylem fiber cell walls in the atpll16 mutant were thicker than those of the wild type. On the contrary, AtPLL16 overexpression resulted in expansion of the phloem and a dramatic change in the xylem-to-phloem ratios. Altogether, our data suggest that AtPLL16 as a pectate lyase plays an important role during vascular development in Arabidopsis.

Calmodulin-Domain Protein Kinase PiCDPK1 Interacts with the 14-3-3-like Protein NtGF14 to Modulate Pollen Tube Growth

“…For example, a homolog of Epsin 3, an accessory protein that facilitates vesicle biogenesis, identified in this study could potentially play a role in the deposition and recycling of wall materials at the tube tip, as Epsin 3 was shown to regulate vacuolar and secretory transport through the trans-golgi network in conjunction with another EPSIN protein [41]. Another protein, Pectate lyase 8 (PLL8), likely influences the pectin content as the up or down-regulation of a related family member alters the pectin content and vascular formation in Arabidopsis [37]. Pectin is a component of pollen tube walls, and at the pollen tube tip, it is the sole component [47], and hence, the pectin dynamics are important for growth responses in these cells.…”

Comprehensive Analysis of the Pectate Lyase Gene Family and the Role of FaPL1 in Strawberry Softening

“…Notably, FaPL5 was clustered with AtPLL19 in Group I, which is different from the other six ripening related FaPLs (Figure 2). AtPLL19 was identified by its xylem-specific expression in Arabidopsis [32]. Combined with the fact that FaPL5 had the lowest expression among the seven ripening related FaPLs (Figure 5B), it can be speculated that FaPL5 may mainly function in xylem vascular development rather than fruit softening, which needs further research.…”

Rhamnogalacturonan lyase 1 (RGL1), as a suppressor of E3 ubiquitin ligase Arabidopsis thaliana ring zinc finger 1 (AtRZF1), is involved in dehydration response to mediate proline synthesis and pectin rhamnogalacturonan‐I composition

“…Collectively, the transcriptional co-regulation between AtRZF1 and RGL1 plays an important in the osmotic stress response through the Pro biosynthesis and cell wall pectin composition-mediated pathway. Bai et al (2023) reported that pectate lyase may directly impact the cell wall integrity pathway, thereby influencing the components of the cell wall and ultimately driving the development of the xylem and phloem. In mature inflorescence stems of Arabidopsis, xylem cells typically maintain six to eight vascular bundles (Turner & Somerville, 1997).…”

“…Recent reports have shown that the Pectate Lyase-Like (PLL) protein, which is an enzyme that breaks down pectin, affects root growth, soluble sugar levels, and vascular development in Arabidopsis (Bai et al, 2023;Sun & Nocker, 2010). As the transcript levels of RGL1 affect pectin contents and primary root elongation, we investigated the influence of RGL1 expression levels on vascular development in plant inflorescence stems.…”