Involvement of nitrogen in storage root growth and related gene expression in sweet potato (Ipomoea batatas)

Abstract

Nitrogen (N) could affect storage root growth and development of sweet potato. To manage external N concentration fluctuations, plants have developed a wide range of strategies, such as growth changes and gene expression.• Five sweet potato cultivars were used to analyse the functions of N in regulating storage root growth. Growth responses and physiological indicators were measured to determine the physiological changes regulated by different N concentrations. Expression profiles of related genes were analysed via microarray hybridization data and qRT-PCR analysis to reveal the molecular mechanisms of storage root growth regulated by different N concentrations.• The growth responses and physiological indicators of the five cultivars were changed by N concentration. The root fresh weight of two of the sweet potato cultivars, SS19 and GS87, was higher under low N concentrations compared with the other cultivars. SS19 and GS87 were found to be having greater tolerance to low N concentration. The expression of N metabolism and storage root growth related genes was regulated by N concentration in sweet potato.• These results reveal that N significantly regulated storage root growth. SS19 and GS87were more tolerant to low N concentration and produced greater storage root yield (at 30 days). Furthermore, several N response genes were involved in both N metabolism and storage root growth.

Evaluation and validation of suitable reference genes for quantitative real-time PCR analysis in lotus (Nelumbo nucifera Gaertn.)

“…To verify the reliability of the previously selected reference genes, NnEXPA1 was chosen for expression analysis. NnEXPA1, a member of the EXPA (α-expansin) subfamily, is associated with EXPA proteins that play a crucial role in cell wall loosening and cell expansion, contributing to various plant developmental processes such as internode elongation, root growth 29 , seed development 30 , endosperm expansion 31 , and nodule formation 32 . When employed as internal controls with different reference genes tailored to specific conditions, no significant expression discrepancies were detected among the recommended candidates.…”

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

“…However, N utilization in cultivars with different N tolerances has rarely been reported. N also affects storage root formation and expansion at the early growth stage, and previous studies showed that moderate N deficiency or low N conditions promote root growth and differentiation, while excessive N apparently inhibits root development (Si et al, 2018; Villordon et al, 2013; Yao et al, 2020). Moreover, a previous study showed that, under the same N levels, treatment with ammonium N resulted in higher storage root yield by promoting young root growth and development and increasing the number of storage roots during the early stage of storage root formation (Si et al, 2018).…”

Regulation of root development in nitrogen-susceptible and nitrogen-tolerant sweet potato cultivars under different nitrogen and soil moisture conditions

“…The increasing demand for sweet potatoes in recent years can be attributed to their adaptability and nutritional value. Nitrogen (N) is an important nutrient element affecting sweet potato growth [ 2 ]. Previous studies have shown that a low N supply can stimulate root growth and differentiation in sweet potatoes, while high rates of N application can lead to root lignification and hinder storage root formation [ 3 , 4 ].…”