Abstract
BackgroundNitrogen (N), referred to as a “life element”, is a macronutrient essential for optimal plant growth and yield production. Amino acid (AA) permease (AAP) genes play pivotal roles in root import, long-distance translocation, remobilization of organic amide-N from source organs to sinks, and other environmental stress responses. However, few systematic analyses of AAPs have been reported in Brassica napus so far.ResultsIn this study, we identified a total of 34 full-length AAP genes representing eight subgroups (AAP1–8) from the allotetraploid rapeseed genome (AnAnCnCn, 2n = 4x = 38). Great differences in the homolog number among the BnaAAP subgroups might indicate their significant differential roles in the growth and development of rapeseed plants. The BnaAAPs were phylogenetically divided into three evolutionary clades, and the members in the same subgroups had similar physiochemical characteristics, gene/protein structures, and conserved AA transport motifs. Darwin’s evolutionary analysis suggested that BnaAAPs were subjected to strong purifying selection pressure. Cis-element analysis showed potential differential transcriptional regulation of AAPs between the model Arabidopsis and B. napus. Differential expression of BnaAAPs under nitrate limitation, ammonium excess, phosphate shortage, boron deficiency, cadmium toxicity, and salt stress conditions indicated their potential involvement in diverse nutrient stress responses.ConclusionsThe genome-wide identification of BnaAAPs will provide a comprehensive insight into their family evolution and AAP-mediated AA transport under diverse abiotic stresses. The molecular characterization of core AAPs can provide elite gene resources and contribute to the genetic improvement of crop stress resistance through the modulation of AA transport.
Highlights
Nitrogen (N), referred to as a “life element”, is a macronutrient essential for optimal plant growth and yield production
Genome-wide identification of amino acid permease (AAP) genes To identify the AAP family members in Brassica species, we used the Amino acid (AA) sequences of AtAAPs to perform BLASTp queries against the genome databases of B. rapa (‘Chiifu-401’), B. oleracea (‘TO1000’), and B. napus (‘Darmor-bzh’)
It can be found that the number of AAPs in B. napus was similar to the sum of AAPs in both B. rapa and B. oleracea
Summary
Nitrogen (N), referred to as a “life element”, is a macronutrient essential for optimal plant growth and yield production. Seed yield and protein content are largely reliant on abundant accumulation of nitrogen (N), which is a macronutrient indispensable for optimal plant growth and organ development [1]. Plants absorb mainly inorganic N nutrients in the form of nitrate (NO3−) and ammonium (NH4+), some of which are assimilated into amino acids (AAs) directly in the roots or were translocated to the shoots. Plants can directly transport AAs and other organic N compounds into roots in soils [2]. Efficient uptake and translocation of AAs are favorable for yield production, and favorable for plant resistance against various stresses [4,5,6,7]
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