The different tolerance to magnesium deficiency of two grapevine rootstocks relies on the ability to cope with oxidative stress

Abstract

Background: Magnesium (Mg) deficiency causes physiological and molecular responses, already dissected in several plant species. The study of these responses among genotypes showing a different tolerance to the Mg shortage can allow identifying the mechanisms underlying the resistance to this nutritional disorder. To this aim, we compared the physiological and molecular responses (e.g. changes in root metabolome and transcriptome) of two grapevine rootstocks exhibiting, in field, different behaviors with respect to Mg shortage (1103P, tolerant and SO4 susceptible).

Results: The two grapevine rootstocks confirmed, in a controlled growing system, their behavior in relation to the tolerance to Mg deficiency. Differences in metabolite and transcriptional profiles between the roots of the two genotypes were mainly linked to antioxidative compounds and the cell wall constituents. In addition, differences in secondary metabolism, in term of both metabolites (e.g. alkaloids, terpenoids and phenylpropanoids) and transcripts, assessed between 1103P and SO4 suggest a different behavior in relation to stress responses particularly at early stages of Mg deficiency.

Conclusions: Our results suggested that the higher ability of 1103P to tolerate Mg shortage is mainly linked to its capability of coping, faster and more efficiently, with the oxidative stress condition caused by the nutritional disorder.

Keywords: Grapevine rootstocks; Magnesium deficiency; Metabolome and transcriptome.

Fig. 1

Details of old leaf of SO4 and 1103P cuttings grown for 14 days in presence (+Mg) and absence of Mg (−Mg)

Fig. 2

Mean SPAD index (a) and S/R (b) values of SO4 and 1103P microcuttings grown for 14 days in presence (+Mg) and absence of Mg (−Mg). Data were expressed as mean ± SEM of data from three growth independent experiments (n = 3). The statistical significance was determined by means of Student’s t-test. (∗P < 0.05) using the GraphPad InStat Program (version 5.0)

Fig. 3

Total shoot soluble sugar concentration of SO4 and 1103P microcuttings grown for 14 days in presence (+Mg) and absence of Mg (−Mg). Data were expressed as mean ± SEM of data from three growth independent experiments (n = 3). The statistical significance was determined by means of Student’s t-test. (∗P < 0.05) using the GraphPad InStat Program (version 5.0)

Fig. 4

Shoot (a) and root (b) Mg concentration of SO4 and 1103P microcuttings grown for 14 days in presence (+Mg) and absence of Mg (−Mg). Data were expressed as mean ± SEM of data from three growth independent experiments (n = 3). The statistical significance was determined by means of Student’s t-test. (∗∗P < 0.01, ∗∗∗P < 0.001) using the GraphPad InStat Program (version 5.0)

Fig. 5

Metabolites differentially abundant in roots between 1103P and SO4 depending on the growth condition. (a) Metabolites specifically modulated at 4 days in presence (+Mg) and absence (−Mg) of Mg and modulated between the two genotypes in both nutritional conditions. (b) Metabolites specifically modulated at 14 days in presence (+Mg) and absence (−Mg) of Mg and modulated between the two genotypes in both nutritional conditions

Fig. 6

Differentially abundant metabolites between 1103P and SO4 linked to stress responses. The Log₁₀(ratio) is shown by the color scale (green indicates a decrease and red an increase in metabolite abundance between 1103P and SO4). The analysis was carried out using MapMan software (https://mapman.gabipd.org/)

Fig. 7

Transcripts differentially expressed in roots between 1103P and SO4 depending on the growth condition. (a) Transcripts specifically modulated at 4 days in presence (+Mg) and absence (−Mg) of Mg and modulated between the two genotypes in both nutritional conditions. (b) Transcripts specifically modulated at 14 days in presence (+Mg) and absence (−Mg) of Mg and modulated between the two genotypes in both nutritional conditions

Fig. 8

Differentially expressed transcripts between 1103P and SO4 linked to stress responses. The Log₂(ratio) is shown by the color scale (green indicates a decrease and red an increase in transcript abundance between 1103P and SO4). The analysis was carried out using MapMan software (https://mapman.gabipd.org/)