Knockout of the S-acyltransferase Gene, PbPAT14, Confers the Dwarf Yellowing Phenotype in First Generation Pear by ABA Accumulation

Abstract

The development of dwarf fruit trees with smaller and compact characteristics leads to significantly increased fruit production, which is a major objective of pear (Pyrus bretschneideri) breeding. We identified the S-acylation activity of PbPAT14, an S-acyltransferase gene related to plant development, using a yeast (Saccharomyces cerevisiae) complementation assay, and also PbPAT14 could rescue the growth defect of the Arabidopsis mutant atpat14. We further studied the function of PbPAT14 by designing three guide RNAs for PbPAT14 to use in the CRISPR/Cas9 system. We obtained 22 positive transgenic pear lines via Agrobacterium-mediated transformation using cotyledons from seeds of Pyrus betulifolia (‘Duli’). Six of these lines exhibited the dwarf yellowing phenotype and were homozygous mutations according to sequencing analysis. Ultrastructure analysis suggested that this dwarfism was manifested by shorter, thinner stems due to a reduction in cell number. A higher level of endogenous abscisic acid (ABA) and a higher transcript level of the ABA pathway genes in the mutant lines revealed that the PbPAT14 function was related to the ABA pathway. Overall, our experimental results increase the understanding of how PATs function in plants and help elucidate the mechanism of plant dwarfism.

Genetic Variation in ZmPAT7 Contributes to Tassel Branch Number in Maize

“…Previous studies suggested that S-acyltransferases play an important role in regulating plant architecture in plants [ 23 , 24 , 25 , 26 ]. Therefore, we focused on GRMZM2G010011 to further validate its function.…”

“…For instance, OsPAT15 regulates plant architecture by altering the tiller in rice [ 24 ], and overexpression of OsPAT15 results in increased branch and seed yield in Brassica napus [ 37 ]. Knockout lines of PbPAT14 exhibited the dwarf yellowing phenotype, and the function of PbPAT14 was related to the ABA pathway [ 25 ]. In addition, Hemsley et al (2005) reported an S-acyltransferase gene in Arabidopsis , Tip Growth Defective 1 ( TIP1 ) /PAT24 , which exhibits impairment in root hair elongation and defective growth of pollen tubes [ 23 ].…”

Potential roles of melatonin and ABA on apple dwarfing in semi-arid area of Xinjiang China

“…This leds to decrease photosynthesis by promoting ABA-mediated chlorophyll degradation ( Asad et al, 2019 ) and reducing carbon dioxide in-take and therefore retards apple tree growth. Similarly, the pear trees which accumulated with ABA also show dwarfing phenotype after knockout of PbPAT14 ( Pang et al, 2019 ). The similar phenomenon of dwarfing phenotype due to ABA accumulation was also found in Gerbera hybrida and Arabidopsis thaliana ( Yang, Worley & Udvardi, 2015 ; Ren et al, 2018 ).…”

“…ABA level is induced by drought stress. Its metabolic pathway has been well studied ( Shu et al, 2016 ; Ren et al, 2018 ; Pang et al, 2019 ). Shi et al (2021) reported that the drought-induced OsAAO3 regulates rice growth and development.…”

Induced Genetic Variations in Fruit Trees Using New Breeding Tools: Food Security and Climate Resilience

“…In the dwarf pear ( Pyrus bretschneideri ), the tree achieved enhanced yield; the loss-of-function mutant of the PbPAT14 gene was generated by the CRISPR/Cas9 system. Sequence analysis revealed that out of 22 dwarf yellow lines, six were homozygous mutants and had an elevated level of endogenous abscisic acid (ABA) [ 152 ].…”