Gas exchange, vine performance and modulation of secondary metabolism in Vitis vinifera L. cv Barbera following long-term nitrogen deficit

Cecilia Squeri,Stefano Poni,Marco Trevisan,Luigi Lucini,Alessandra Garavani,Begoña Miras-Moreno,Matteo Gatti

doi:10.1007/s00425-021-03590-8

Cecilia Squeri, Stefano Poni + Show 5 more

Open Access

https://doi.org/10.1007/s00425-021-03590-8

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Journal: Planta	Publication Date: Feb 22, 2021
Citations: 3	License type: open-access

Affiliation: Università Cattolica del Sacro Cuore

Abstract

Main ConclusionA reprogramming of secondary metabolism to acclimate to nitrogen deficiency was seen in grapevine eliciting an accumulation of strigolactones and jasmonate. This response links with photosynthetic compensation and enhanced ripening.In addition to the metabolism directly related to nitrogen assimilation, long-term nitrogen depletion may affect plant secondary metabolism, in turn affecting grapevine performance. In this work, the effect of nitrogen deficit was investigated in V. vinifera cv. Barbera potted vines following three years of deprivation, using a combination of morpho-physiological assessments and mass spectrometry-based untargeted metabolomics. Plants grown under nitrogen limitation showed reduced growth and even more curtailed yields, lowered SPAD values, and a quite preserved leaf gas exchange, compared to plants grown under non-limiting nitrogen availability. Ripening was decidedly accelerated, and berry composition improved in terms of higher sugar and phenolic contents under nitrogen-limiting conditions. Metabolomics showed the broad involvement of secondary metabolism in acclimation to nitrogen deficiency, including a distinctive modulation of the phytohormone profile. Several nitrogen-containing metabolites were down accumulated under nitrogen-limiting conditions, including alkaloids, glucosinolates, hypoxanthine, and inosine. On the other hand, phenylpropanoids showed an accumulation trend. Concerning the recruitment of hormones, nitrogen deprivation elicited an accumulation of strigolactones and jasmonate. Noteworthy, both strigolactones and jasmonates have been previously related to increased photosynthetic efficiency under abiotic stress. Furthermore, the severe reduction of lateral shoot development we recorded in N-deprived vines is consistent with the accumulation of strigolactones. Overall, our results suggest that nitrogen deprivation induced a rather broad metabolic reprogramming, mainly including secondary metabolism and hormones profile, reflected in the modulation of photosynthetic performance, canopy growth, and possibly fruit quality.

Highlights

Despite the considerable know-how and progress made over the last decades in vine physiology and cultural practices (Poni et al 2018; Jamali et al 2020), a large number of poorly explained or unknown cause-effect relationships between environmental and agronomical inputs and outputs does exist especially in the realm of grape production
When SPAD and A rates data taken on the same leaves were pooled over different sampling dates and shoot positions, the resulting correlation was not significant
As a result of relative variation of A and g s, intrinsic WUE (A/ gs) of N + leaves significantly diminished at any date in basal and median shoot portions, whereas the trend was milder in apical leaves (Fig. 1j–l)

Summary

Introduction

Despite the considerable know-how and progress made over the last decades in vine physiology and cultural practices (Poni et al 2018; Jamali et al 2020), a large number of poorly explained or unknown cause-effect relationships between environmental and agronomical inputs and outputs does exist especially in the realm of grape production. N-deficiency is especially harmful when occurring around flowering (May 2004) It can severely curtail the current season fruit-set while having adverse effects on next-year bud induction (Guilpart et al 2014). N excess can likely be even more detrimental as it can lead to excessive vigor and consequent ripening delay, poor wood maturation and season bud induction and differentiation (Mendez-Costabel et al 2014; Mundy, 2008). It compacts clusters with large berries and less favourable skin-to-berry ratio (Gatti et al 2017) and downregulates genes involved in anthocyanin biosynthesis (Soubeyrand et al 2014). N is involved in the leaf longevity process, as it has been demonstrated that photosynthetic decline in a mature grapevine leaf is linked to increased N export towards growing sinks (Poni et al 1994; Pyung et al 2007)

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