Nitrogen utilization characteristics and early storage root development in nitrogen‐tolerant and nitrogen‐susceptible sweet potato

In recent years, sweet potato has been cultivated not only in marginal lands but also in fertile plains in northern China. The fertile nitrogen (N)‐rich soil may inhibit storage root formation. Cultivars with different N tolerances and split application of reduced N rates should be considered. To in...

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Bibliographic Details
Published in:Physiologia plantarum 2021-11, Vol.173 (3), p.1090-1104
Main Authors: Duan, Wenxue, Zhang, Haiyan, Xie, Beitao, Wang, Baoqing, Hou, Fuyun, Li, Aixian, Dong, Shunxu, Qin, Zhen, Wang, Qingmei, Zhang, Liming
Format: Article
Language:English
Subjects:
Amylases
Cultivars
Flavonoids
Gene expression
Genes
Metabolic pathways
Nitrogen
Nutrition
Organs
Potatoes
Root development
Roots
Starch
Sweet potatoes
Tolerances
Urea
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Summary:In recent years, sweet potato has been cultivated not only in marginal lands but also in fertile plains in northern China. The fertile nitrogen (N)‐rich soil may inhibit storage root formation. Cultivars with different N tolerances and split application of reduced N rates should be considered. To investigate the effects of N on the N utilization, root differentiation, and storage root formation of cultivars with different N tolerances, the cultivars Jishu26 (J26) and Xushu32 (X32) were treated with three N levels supplied by urea: 0 (N0), 200 (N1) and 400 mg kg−1 (N2). With increasing N rates, “X32” absorbed less N in plants and distributed more N to developing storage roots than “J26.” The storage root development of “J26” was sensitive to both N1 and N2, while that of “X32” was only sensitive to N2. High N nutrition upregulated the expression of certain genes during storage root formation, such as PAL, CHI, F3H, C4H, 4CL, CAD, α‐amylase, and β‐amylase. Under N1 and N2, “X32” led to an increased sugar supply in sink organs and downregulated the expression of genes related to lignin and flavonoid synthesis, which promoted the C flux toward starch metabolism, thus reducing lignification and promoting starch accumulation during storage root formation. These results provide evidence for the effects of N on the C distribution in different metabolic pathways by regulating the expression of related key genes. N‐tolerant cultivars are suitable in fertile plain areas because of the earlier formation of storage roots under high N conditions.
ISSN:0031-9317
1399-3054
DOI:10.1111/ppl.13504