Seed characterization and early nitrogen metabolism performance of seedlings from Altiplano and coastal ecotypes of Quinoa
BMC PLANT BIOLOGY
Authors: Pinto-Irish, Katherine; Coba de la Pena, Teodoro; Ostria-Gallardo, Enrique; Ibanez, Cristian; Briones, Vilbett; Vergara, Alexander; Alvarez, Rodrigo; Castro, Catalina; Sanhueza, Carolina; Castro, Patricio A.; Bascunan-Godoy, Luisa
Abstract
Background Early seed germination and a functional root system development during establishment are crucial attributes contributing to nutrient competence under marginal nutrient soil conditions.Chenopodium quinoaWilld (Chenopodiaceae) is a rustic crop, able to grow in marginal areas. Altiplano and Coastal/Lowlands are two representative zones of quinoa cultivation in South America with contrasting soil fertility and edaphoclimatic conditions. In the present work, we hypothesize that the ecotypes of Quinoa from Altiplano (landrace Socaire) and from Coastal/Lowland (landrace Faro) have developed differential adaptive responses in order to survive under conditions of low availability of N in their respective climatic zones of Altiplano and Lowlands. In order to understand intrinsic differences for N competence between landraces, seed metabolite profile and germinative capacity were studied. Additionally, in order to elucidate the mechanisms of N uptake and assimilation at limiting N conditions during establishment, germinated seeds of both landraces were grown at either sufficient nitrate (HN) or low nitrate (LN) supply. We studied the photosynthetic performance, protein storage, root morphometrical parameters, activity and expression of N-assimilating enzymes, and the expression of nitrate transporters of roots in plants submitted to the different treatments. Results Seeds from Socaire landrace presented higher content of free N-related metabolites and faster seed germination rate compared to Faro landrace. Seedlings of both ecotypes presented similar physiological performance at HN supply, but at LN supply their differences were exalted. At LN, Socaire plants showed an increased root biomass (including a higher number and total length of lateral roots), a differential regulation of a nitrate transporter (aNPF6.3-like homologue) belonging to the Low Affinity Transport System (LATS), and an upregulation of a nitrate transporter (aNRT2.1-like homologue) belonging to the High Affinity nitrate Transport System (HATS) compared to Faro. These responses as a whole could be linked to a higher amount of stored proteins in leaves, associated to an enhanced photochemical performance in Altiplano plants, in comparison to Lowland quinoa plants. Conclusions These differential characteristics of Socaire over Faro plants could involve an adaptation to enhanced nitrate uptake under the brutal unfavorable climate conditions of Altiplano.
Chondroitin synthase-3 regulates nucleus pulposus degeneration through actin-induced YAP signaling
FASEB JOURNAL
Authors: Wei, Leixin; Cao, Peng; Xu, Chen; Zhong, Huajian; Wang, Xiukun; Bai, Meizhu; Hu, Bo; Wang, Ruizhe; Liu, Ning; Tian, Ye; Chen, Huajiang; Li, Jinsong; Yuan, Wen
Abstract
Loss of chondroitin sulfate (CS) has been reported to play a key role during intervertebral disc degeneration (IDD). However, the detailed mechanism of CS and its synthases have not been elucidated. Since CS is mainly synthesized by chondroitin synthases 3 (Chsy3), here, the Chsy3 knockout mice are generated by using CRISPR-Cas9 and semi-cloning technology to study its mechanism during IDD. We find that CS and Chsy3 expression are decreased during IDD both in human and mice nucleus pulposus (NP) tissue, and knockout of Chsy3 shows that spontaneous IDD phenotype resembles that of human samples in theChsy3(-/-)mice. Taking advantage of RNA-Seq data, we confirm increased catabolic and decreased anabolic changes inChsy3(-/-)NP cells. By using bioinformatic analysis and validation, we find that Hippo signaling pathway is significantly downregulated, and the activation of Yap1 is mainly affected inChsy3(-/-)NP cells. Furthermore, functional analyses have shown that Chsy3 could regulate NP cell degeneration by Actin tension mediated activation of Yap1, which is independent of Hippo/Lats signaling. In summary, our findings reveal a novel mechanism that depletion of CS-related Chsy3 can cause spontaneous intervertebral disc degeneration by mediating Yap activation through CS-related actin-tension in NP cells.