Plant metabolism and defence strategies in the flowering stage: Time‐dependent responses of leaves and flowers under attack. (6th June 2022)

• Record Type: Journal Article
• Authors: Chrétien, Lucille T. S.; Khalil, Alix; Gershenzon, Jonathan; Lucas‐Barbosa, Dani; Dicke, Marcel; Giron, David
• Is Part Of: Plant, cell and environment. Volume 45:Number 9(2022)
• Page Start: 2841
• Page End: 2855
• Publication Date: 2022-06-06
• Subjects: Brassica nigra (Brassicaceae) -- direct resistance -- florivorous insects -- flowering stage -- multiple attack -- phytopathogens -- plant primary metabolism -- plant secondary metabolism -- tolerance; Plant physiology -- Periodicals; Plant cells and tissues -- Periodicals; Plant communities -- Periodicals; 581.105
• DOI: 10.1111/pce.14363
• Languages: English
• ISSNs: 0140-7791

Abstract

Abstract: Plants developing into the flowering stage undergo major physiological changes. Because flowers are reproductive tissues and resource sinks, strategies to defend them may differ from those for leaves. Thus, this study investigates the defences of flowering plants by assessing processes that sustain resistance (constitutive and induced) and tolerance to attack. We exposed the annual plant Brassica nigra to three distinct floral attackers (caterpillar, aphid and bacterial pathogen) and measured whole‐plant responses at 4, 8 and 12 days after the attack. We simultaneously analysed profiles of primary and secondary metabolites in leaves and inflorescences and measured dry biomass of roots, leaves and inflorescences as proxies of resource allocation and regrowth. Regardless of treatments, inflorescences contained 1.2 to 4 times higher concentrations of primary metabolites than leaves, and up to 7 times higher concentrations of glucosinolates, which highlights the plant's high investment of resources into inflorescences. No induction of glucosinolates was detected in inflorescences, but the attack transiently affected the total concentration of soluble sugars in both leaves and inflorescences. We conclude that B. nigra evolved high constitutive rather than inducible resistance to protect their flowers; plants additionally compensated for damage by attackers via the regrowth of reproductive parts. This strategy may be typical of annual plants. Abstract : Results show that flowering Brassica nigra protect their inflorescences with constitutive resistance rather than with inducible resistance, and compensate for floral dammage with early changes in primary metabolism and regrowth. Metabolic profiles reflected high resource investment into reproduction.