Elongation Changes of Exploratory and Root Hair Systems Induced by Aminocyclopropane Carboxylic Acid and Aminoethoxyvinylglycine Affect Nitrate Uptake andBnNrt2.1andBnNrt1.1Transporter Gene Expression in Oilseed Rape

Abstract

Ethylene is a plant hormone that plays a major role in the elongation of both exploratory and root hair systems. Here, we demonstrate in Brassica napus seedlings that treatments with the ethylene precursor, aminocyclopropane carboxylic acid (ACC) and the ethylene biosynthesis inhibitor, aminoethoxyvinylglycine (AVG), cause modification of the dynamic processes of primary root and root hair elongation in a dose-dependent way. Moreover, restoration of root elongation in AVG-treated seedlings by 1 mM L-glutamate suggested that high concentrations of AVG affect root elongation through nonoverlapping ethylene metabolic pathway involving pyridoxal 5#-P-dependent enzymes of nitrate (N) metabolism. In this respect, treatments with high concentrations of ACC and AVG (10 mM) over 5 d revealed significant differences in relationships between root growth architecture and N uptake capacities. Indeed, if these treatments decreased severely the elongation of the exploratory root system (primary root and lateral roots) they had opposing effects on the root hair system. Although ACC increased the length and number of root hairs, the rate of N uptake and the transcript level of the N transporter BnNrt2.1 were markedly reduced. In contrast, the decrease in root hair length and number in AVG-treated seedlings was overcompensated by an increase of N uptake and BnNrt2.1 gene expression. These root architectural changes demonstrated that BnNrt2.1 expression levels were more correlated to the changes of the exploratory root system than the changes of the root hair system. The difference between treatments in N transporters BnNrt1.1 and BnNrt2

Salicylic acid alleviates adverse effects of heat stress on photosynthesis through changes in proline production and ethylene formation

“…[38][39][40][41] In contrast, Leblanc et al 42 have shown that N uptake and nitrate transporter BnNrt2.1 transcript levels were markedly reduced in the presence of ethylene promoter in Brassica napus, but were increased in the presence of ethylene inhibitor. Li et al 43 have observed inhibition of ACS expression in the presence of SA in Lycopersicon esculentum.…”

Ethylene negatively regulates aluminium-induced malate efflux from wheat roots and tobacco cells transformed with TaALMT1

“…Leblanc et al (2008) showed that treatment of oilseed rape seedlings with ACC and AVG reduced and enhanced nitrate uptake, respectively, by monitoring 15 N uptake. They suggested that a posttranscriptional regulation of nitrate transporters may be involved in the regulation of nitrate transport by ethylene (Leblanc et al , 2008).…”

Nitrogen fertility and abiotic stresses management in cotton crop: a review

“…Inhibited cotton root growth (Armstrong and Drew 2002) reduced plasma membrane H + -ATPase activity, impaired nutrient acquisition, and higher 1-aminocyclopropene-1-carboxlic acid (ACC) in root tissues inhibited root growth Fig. 2 Waterlogging-induced aerenchyma formation in rice (a) and wheat (b) (Mustroph and Albrecht, 2003), while they are absent in cotton (c) (Conaty et al 2008) waterlogging Oxygen (Leblanc et al 2008) (Fig. 4).…”