Pectate Lyase Gene VvPL1 Plays a Role in Fruit Cracking of Table Grapes

Abstract

Fruit cracking seriously affects the commercial value of table grapes. To explore whether cell wall disassembly influences grape berry cracking, first, the differences in the cell wall metabolism were compared between cracking-resistant "Shennongjinhuanghou" (SN) and cracking-susceptible "Xiangfei" (XF) varieties. Our results showed that cell wall disassembly events were extremely different between "SN" and "XF." The cracking-resistant "SN" had a higher pectinmethylesterase activity in the early stage and lower polygalacturonase, β-galactosidase, pectate lyase, and cellulase activities from veraison, cooperatively yielding higher ionically bound pectin, covalently bound pectin, hemicellulose, and lower water-soluble pectin, leading to a stronger skin break force and elasticity and conferring "SN" with higher cracking resistance. Furthermore, the function of the VvPL1 gene in fruit cracking was verified by heterologously transforming tomatoes. The transgenic experiment showed that overexpressed fruits had a higher activity of pectate lyase from the breaking stage and a lower level of covalently bound pectin, ionically bound pectin, cellulose, and hemicellulose and a higher level of water-soluble pectin at the red ripe stage, which resulted in a significantly reduced skin break force and flesh firmness and increased fruit cracking incidences. In conclusion, our results demonstrated that the cracking susceptibility of the grape berry is closely related to cell wall disassembly events and VvPL1 plays an important role in fruit cracking.

Overexpression of the Rubus idaeus Polygalacturonases Gene RiPG2 Accelerates Fruit Softening in Solanum lycopersicum

“…Previous studies have shown that increased activity of these enzymes and proteins leads to fruit softening [63]. The low activity of pectinase synergistically inhibited the degradation of cell walls and increased their resistance to cleavage after the color change stage in grapes [64]. The genes encoding these enzymes and proteins may also have synergistic effects with each other [35].…”

Constitutive expression of apple endo‐POLYGALACTURONASE1 in fruit induces early maturation, alters skin structure and accelerates softening

“…A dramatic result of the altered skin structure was greatly increased water permeance and subsequent post‐harvest fruit water loss. Increased skin cracking can be a consequence of altered cell wall structure, as shown in tomato where the cell wall structure was affected by silencing of the β‐galactosidase gene TBG6 , silencing of SlEXP1/SlPG2a , or by overexpression of the grape PL VvPL1 (Jiang et al., 2019; Moctezuma et al., 2003; Yu et al., 2023). The higher permeance of apple fruit in the PGox lines was also related to microcracking of the cuticle.…”

PpAmy1 Plays a Role in Fruit-Cracking by Regulating Mesocarp Starch Hydrolysis of Nectarines

“…Numerous factors have been identified in research as closely associated with fruit-cracking, including temperature, moisture, light, hormones, mineral elements, skin mechanical properties, and skin strength. , However, the specific causes of fruit-cracking can vary among the different species. The excessive enlargement of fruit flesh cells, exceeding the tolerance of the fruit skin, is often considered as a significant factor leading to fruit-cracking. − One important reason for cell enlargement is the regulation of osmotic pressure by cell inclusions . Soluble sugars are crucial cellular components that not only contribute to fruit growth and development, but also provide the osmotic driving force for fruit cell expansion .…”

“…6−10 One important reason for cell enlargement is the regulation of osmotic pressure by cell inclusions. 11 Soluble sugars are crucial cellular components that not only contribute to fruit growth and development, but also provide the osmotic driving force for fruit cell expansion. 12 Lu and Lin (2012) discovered that cracked apples had 20% higher levels of soluble solids and titratable acid content compared to normal fruits, along with a 40% lower osmotic potential and a 60% higher swelling pressure.…”