Metabolomic markers and physiological adaptations for high phosphate utilization efficiency in rice

Abstract

Utilizing phosphate more efficiently is crucial for sustainable crop production. Highly efficient rice (Oryza sativa) cultivars have been identified and this study aims to identify metabolic markers associated with P utilization efficiency (PUE). P deficiency generally reduced leaf P concentrations and CO 2 assimilation rates but efficient cultivars were reducing leaf P concentrations further than inefficient ones while maintaining similar CO 2 assimilation rates. Adaptive changes in carbon metabolism were detected but equally in efficient and inefficient cultivar groups. Groups furthermore did not differ with respect to partial substitutions of phospholipids by sulfoand galactolipids. Metabolites significantly more abundant in the efficient group, such as sinapate, benzoate and glucoronate, were related to antioxidant defence and may help alleviating oxidative stress caused by P deficiency. Sugar alcohols ribitol and threitol were another marker metabolite for higher phosphate efficiency as were several amino acids, especially threonine. Since these metabolites are not known to be associated with P deficiency, they may provide novel clues for the selection of more P efficient genotypes. In conclusion, metabolite signatures detected here were not related to phosphate metabolism but rather helped P efficient lines to keep vital processes functional under the adverse conditions of P starvation.

Genetic and physiological traits for internal phosphorus utilization efficiency in rice

“…Any potentially preferential allocation to roots rather than developing leaves in the high-PUE genotypes did, however, not reduce the biomass of leaves in these genotypes in comparison to the low-PUE genotypes ( S3 Fig ). Thus, the high-PUE genotypes appeared to more rapidly reduce P concentrations in newly developed and older leaves alike, and likely allocated the extra P to root growth, which would be an efficient strategy to outgrow P deficiency as new roots will increase the amount of P taken up by the plant [ 29 , 30 ] investigated to what extent reduced leaf P concentrations affect leaf photosynthetic efficiency. At the range of P concentrations seen here at T2 in the high-PUE genotypes (< 1.0 mg g -1 ) one may expect reductions in CO 2 assimilation rates by up to 30% and these will be less in IR64 and Taichung with leaf P concentrations well-above 1.0 mg g -1 .…”

“…At the range of P concentrations seen here at T2 in the high-PUE genotypes (< 1.0 mg g -1 ) one may expect reductions in CO 2 assimilation rates by up to 30% and these will be less in IR64 and Taichung with leaf P concentrations well-above 1.0 mg g -1 . While this can be compensated to some extent in high-PUE genotypes by producing larger leaves [ 30 ], we may expect the loss of photosynthetic capacity to be more pronounced in the high-PUE genotypes. In this regard one needs to keep in mind that the strategy to preferentially supply P for root growth does not provide additional P uptake in this nutrient solution experiment, while it would do so in plants grown in soil.…”

“…Thus, having more leaves, which was observed in low-PUE genotypes ( S2 Fig ), leads to less efficient utilization of P. This may reflect the relatively high cost newly developing leaves incur in terms of P allocation, which happens at shorter intervals with more rapid leaf emergence. It may therefore be more efficient to develop fewer but larger leaves [ 30 ]. It should be noted that the low-PUE genotypes are modern semi-dwarf rice varieties whereas the high-PUE group consisted of traditional varieties characterized by being generally more vigorous [ 8 ].…”

Analysis of Metabolomic Changes in Lettuce Leaves under Low Nitrogen and Phosphorus Deficiencies Stresses

“…The change of internal small molecular compounds can occur earlier than changes in external characteristics [37]. Previous studies only focused on the changes of metabolites under single nutrient stress, such as nitrogen, phosphorus, potassium or zinc [17][18][19][20]38]. In fact, different nutritional stress can cause changes of the same metabolites.…”

“…Cevallos-Cevallos et al [18] found significant differences in oxo-butanedioic acid, arabitol, and neo-inositol between zinc-deficient and healthy orange trees. The metabolomics of rice leaves under conditions of nitrogen and phosphorus deficiencies were analyzed by Shen [19] and Watanabe et al [20], the stress-resistant substances and amino acid substitution products increased under nitrogen deficiency, with sinapate, benzoate, and glucuronate related to phosphorus deficiency.…”