Abstract:
Amino acid transporters (AATs) play a crucial role in facilitating the movement of amino
acids across cellular membranes, which is vital for the growth and development of plants. Amino
acid permease (AAP), which belongs to the AAT family, has been the subject of extensive functional
research in plants. Although its importance is recognized, a comprehensive grasp of this family’s
dynamics in indica rice remains lacking. In this investigation, a total of 27 AAP genes were identified
in the genome of indica rice. Further, the phylogenetic analysis unveiled that the 69 AAP genes from
both the model species and other plant species could be classified into 16 distinct subfamilies. The
analysis of chromosomal mapping revealed an uneven distribution of the 27 OsAAP genes across the
12 rice chromosomes. Notably, the OsAAP family displayed a total of 10 duplicated gene pairs, along
with the identification of numerous conserved motifs. The examination of cis-elements within OsAAP
genes unveiled that their promoters contain cis-elements related to phytohormones, plant growth
and development, as well as stress responses. Additionally, transcriptome profiling demonstrated
that a substantial portion of these genes exhibited responsiveness to various hormones, with their
activation spanning multiple tissues and developmental stages in rice. The study identified miRNAs
with a specific affinity for OsAAP genes. Out of the 27 OsAAP genes investigated, seventeen were
discovered to be targeted by a total of forty-three miRNAs. Furthermore, the aus allele of OsAAP3
that we named OsAAP17 was validated for its effect on productive tillers and yield, and seventeen
genetic variants of OsAAP17 were found to be associated with a culm number in indica rice. In
addition, indica rice varieties were monomorphic, while aus genotypes displayed polymorphism
for OsAAP17 gene-specific in/dels. Moreover, in Season II (rabi season), it was found that the aus
allele of OsAAP17 increased the number of productive tillers and the single plant yield by 22.55%
and 9.67%, respectively, in a recombinant inbred population created by crossing N22 and JR 201.
Remarkably, this enhancement was more pronounced during the dry cultivation season, highlighting
the influence of environmental factors in the regulation of tiller numbers mediated by OsAAP17.
