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ARS Home » Northeast Area » Kearneysville, West Virginia » Appalachian Fruit Research Laboratory » Innovative Fruit Production, Improvement, and Protection » Research » Publications at this Location » Publication #385310

Research Project: Improving Fruit Crop Traits Through Advanced Genomic, Breeding, and Management Technologies

Location: Innovative Fruit Production, Improvement, and Protection

Title: Polymorphisms and gene expression in the almond IGT family are not correlated to variability in growth habit in major commercial almond cultivars

item MONTESINOS, ALVARO - Agrifood Research And Technology Center Of Aragon
item Dardick, Christopher - Chris
item JOSE RUBIO-CABETAS, MARIA - Agrifood Research And Technology Center Of Aragon
item GRIMPLET, JEROME - Agrifood Research And Technology Center Of Aragon

Submitted to: Plant Physiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/30/2021
Publication Date: N/A
Citation: N/A

Interpretive Summary: Here we examined a set of genes (dubbed IGT) we previously identified in peach that control tree architecture contributed to the natural architectural variation in almond. The results showed that IGT genes are highly conserved in almond and that there were no significant associations found between IGT gene mutations and almond tree shape. Analysis of gene expression revealed the presence of a potential regulator of IGT gene expression called IPA1. The results provide a path forward for breeding efforts in almond and suggest the presence of alleles that may be combined to generate new almond architectures useful for high density orchard systems in the future.

Technical Abstract: Almond breeding programs aimed at selecting cultivars adapted to intensive orchardshave recently focused on the optimization of tree architecture. This multifactorial trait is defined by numerous components controlled by processes such as hormonal responses, gravitropism and light perception. Gravitropism sensing is crucial to control the branch angle and therefore, the tree habit. A gene family, denominated IGT family after a share conserved domain, has been described as involved in the regulation of branch angle in several species, including rice and Arabidopsis, and even in fruit trees like peach. Here we identified six members of this family in almond: LAZY1, LAZY2, TAC1, DRO1, DRO2, IGT-like. After analyzing their protein sequences in forty-one almond cultivars and wild species, little variability was found, pointing a high degree of conservation in this family. Gene expression was analyzed in fourteen cultivars of agronomical interest comprising diverse tree habit phenotypes. Only LAZY1, LAZY2 and TAC1 were expressed in almond shoot tips during the growing season. No relation was established between the expression profile of these genes and the tree habit. However, some insight has been gained in how LAZY1 and LAZY2 are regulated, identifying the IPA1 almond homologues and other transcription factors involved in hormonal responses as regulators of their expression. Besides, we have found various polymorphisms that could not be discarded as involved in a potential polygenic origin of regulation of architectural phenotypes. Therefore, we have established that unlike many species, IGT family genes do not play a critical role in the control of tree habit in currently commercialized almond cultivars, with other gene families contributing to the variability of these traits.