Seed Carotenoid and Tocochromanol Composition of Wild Fabaceae Species Is Shaped by Phylogeny and Ecological Factors

Abstract

Carotenoids distribution and function in seeds have been very scarcely studied, notwithstanding their pivotal roles in plants that include photosynthesis and phytohormone synthesis, pigmentation, membrane stabilization and antioxidant activity. Their relationship with tocochromanols, whose critical role in maintaining seed viability has already been evidenced, and with chlorophylls, whose retention in mature seed is thought to have negative effects on storability, remain also unexplored. Here, we aimed at elucidating seed carotenoids relationship with tocochromanols and chlorophylls with regard to phylogenetic and ecological traits and at understanding their changes during germination. The composition and distribution of carotenoids were investigated in seeds of a wide range of wild species across the Fabaceae (the second-most economically important family after the Poaceae). Photosynthetic pigments and tocochromanols were analyzed by HPLC in mature dry seeds of 50 species representative of 5 subfamilies within the Fabaceae (including taxa that represent all continents, biomes and life forms within the family) and at key timepoints during seedling establishment in three species representative of distinct clades. Total-carotenoids content positively correlated with tocopherols in the basal subfamilies Detarioideae, Cercidoideae, and Dialioideae, and with chlorophylls in the Papilionoideae. Papilionoideae lacked tocotrienols and had the highest total-carotenoids, chlorophyll and γ-tocopherol contents. Interestingly, lutein epoxide was present in 72% of the species including several herbs from different subfamilies. Overall, species original from temperate biomes presented higher carotenoids and lower tocochromanols levels than those from tropical biomes. Also shrub species showed higher carotenoids content than herbs and trees. During germination, total content of photosynthetic pigments increased in parallel to changes in relative abundance of carotenoids: zeaxanthin and anteraxanthin decreased and β-carotene augmented. Notably, the highest contents of nutritionally valuable carotenoids were found in Papilionoideae subfamily to which all pulses of socio-economic importance belong. The major differences in carotenoids and tocochromanols composition across the Fabaceae are apparently related to phylogeny in conjunction with ecological traits such as biome and growth form.

Effects of Aromatic Herb Flavoring on Carotenoids and Volatile Compounds in Edible Oil From Blue Sweet Lupin (Lupinus angustifolius)

“…Although β‐carotene and its isomers were identified as major compounds across the samples, carotenes were found in lower levels than xanthophylls. Earlier studies found that the photosynthetic tissues of lupin and aromatic herbs provide mainly xanthophylls, with lutein being the most predominant carotenoid . Results from the present investigation support the hypothesis of Mellado‐Ortega and Hornero‐Mendez, who speculated extensively on the reason why lutein is the dominant carotenoid in many botanical species, such as legumes and cereals .…”

Desiccation Tolerance in Chlorophyllous Fern Spores: Are Ecophysiological Features Related to Environmental Conditions?

“…The photoprotective role of α-tocopherol is well documented (Munné-Bosch and Alegre, 2002) and is very common in photosynthetic tissues. The other isoforms β and δ are quite rare in most plant species, and γ-tocopherol is more common in seeds (Grusak and DellaPenna, 1999; Fernández-Marín et al 2017). Abbasi et al (2007) found that tobacco seeds increased the amounts of α-tocopherol as DT was acquired during maturation.…”

The conservation value of germplasm stored at the Millennium Seed Bank, Royal Botanic Gardens, Kew, UK

“…The key principles at the core of gene bank operations are the preservation of germplasm identity, maintenance of viability and genetic integrity, and the promotion of access (FAO 2014). In our study, the germplasm quality was analysed in terms of: (1) availability of key data in SBD for taxonomy (plant name), geography (bio-geographic region, country, geo-coordinates and altitude), habitat and population (number of plants found, and sampled and area sampled); (2) current status of plant identification (verified or unverified); and (3) seed quality, quantity and viability.…”