المؤلفون: Jorge C. Berny Mier y Teran, Enéas R. Konzen, Antonia Palkovic, Siu M. Tsai, Idupulapati M. Rao, Stephen Beebe, Paul Gepts

المصدر: BMC Plant Biology, Vol 19, Iss 1, Pp 1-15 (2019)

مصطلحات موضوعية: Abiotic stress, Epistasis, Photosynthate remobilization, Pod harvest index, Quantitative trait loci, Botany, QK1-989

الوصف: Abstract Background Common bean is the most important staple grain legume for direct human consumption and nutrition. It complements major sources of carbohydrates, including cereals, root crop, or plantain, as a source of dietary proteins. It is also a significant source of vitamins and minerals like iron and zinc. To fully play its nutritional role, however, its robustness against stresses needs to be strengthened. Foremost among these is drought, which commonly affects its productivity and seed quality. Previous studies have shown that photosynthate remobilization and partitioning is one of the main mechanisms of drought tolerance and overall productivity in common bean. Results In this study, we sought to determine the inheritance of pod harvest index (PHI), a measure of the partitioning of pod biomass to seed biomass, relative to that of grain yield. We evaluated a recombinant inbred population of the cross of ICA Bunsi and SXB405, both from the Mesoamerican gene pool, to determine the effects of intermittent and terminal drought stresses on the genetic architecture of photosynthate allocation and remobilization in pods of common bean. The population was grown for two seasons, under well-watered conditions and terminal and intermittent drought stress in one year, and well-watered conditions and terminal drought stress in the second year. There was a significant effect of the water regime and year on all the traits, at both the phenotypic and QTL levels. We found nine QTLs for pod harvest index, including a major (17% of variation explained), stable QTL on linkage group Pv07. We also found eight QTLs for yield, three of which clustered with PHI QTLs, underscoring the importance of photosynthate remobilization in productivity. We also found evidence for substantial epistasis, explaining a considerable part of the variation for yield and PHI. Conclusion Our results highlight the genetic relationship between PHI and yield and confirm the role of PHI in selection of both additive and epistatic effects controlling drought tolerance. These results are a key component to strengthen the robustness of common bean against drought stresses.

وصف الملف: electronic resource

العلاقة: http://link.springer.com/article/10.1186/s12870-019-1774-2Test; https://doaj.org/toc/1471-2229Test

الوصول الحر: https://doaj.org/article/a9db0651f4fb4d70adaa73f13268d548Test

المؤلفون: Hiroshi Takagi, Shunsuke Watanabe, Shoma Tanaka, Takakazu Matsuura, Izumi C. Mori, Takashi Hirayama, Hiroshi Shimada, Atsushi Sakamoto

المصدر: BMC Plant Biology, Vol 18, Iss 1, Pp 1-16 (2018)

مصطلحات موضوعية: Allantoate, Allantoin, Arabidopsis thaliana, Catabolic pathway, Nitrogen remobilization, Phytohormone, Botany, QK1-989

الوصف: Abstract Background The ureides allantoin and allantoate are major metabolic intermediates of purine catabolism with high nitrogen-to-carbon ratios. Ureides play a key role in nitrogen utilization in ureide-type legumes, but their effects on growth and development in non-legume plants are poorly understood. Here, we examined the effects of knocking out genes encoding ureide-degrading enzymes, allantoinase (ALN) and allantoate amidohydrolase (AAH), on the vegetative-to-reproductive transition and subsequent growth of Arabidopsis plants. Results The ureide-degradation mutants (aln and aah) showed symptoms similar to those of nitrogen deficiency: early flowering, reduced size at maturity, and decreased fertility. Consistent with these phenotypes, carbon-to-nitrogen ratios and nitrogen-use efficiencies were significantly decreased in ureide-degradation mutants; however, adding nitrogen to irrigation water did not alleviate the reduced growth of these mutants. In addition to nitrogen status, levels of indole-3-acetic acid and gibberellin in five-week-old plants were also affected by the aln mutations. To test the possibility that ureides are remobilized from source to sink organs, we measured ureide levels in various organs. In wild-type plants, allantoate accumulated predominantly in inflorescence stems and siliques; this accumulation was augmented by disruption of its catabolism. Mutants lacking ureide transporters, ureide permeases 1 and 2 (UPS1 and UPS2), exhibited phenotypes similar to those of the ureide-degradation mutants, but had decreased allantoate levels in the reproductive organs. Transcript analysis in wild-type plants suggested that genes involved in allantoate synthesis and ureide transport were coordinately upregulated in senescing leaves. Conclusions This study demonstrates that ureide degradation plays an important role in supporting healthy growth and development in non-legume Arabidopsis during and after transition from vegetative to reproductive stages.

وصف الملف: electronic resource

العلاقة: http://link.springer.com/article/10.1186/s12870-018-1491-2Test; https://doaj.org/toc/1471-2229Test

الوصول الحر: https://doaj.org/article/fd11d9639f4a4b908ebed5717b53b26eTest