The Plant Journal

doi: 10.1111/tpj.14254pmid: N/A

Maron, Lyza

doi: 10.1111/tpj.14525pmid: 31557378

Sall, Khadidiatou; Dekkers, Bas J. W.; Nonogaki, Mariko; Katsuragawa, Yoshihiko; Koyari, Ryosuke; Hendrix, David; Willems, Leo A. J.; Bentsink, Leónie; Nonogaki, Hiroyuki

doi: 10.1111/tpj.14485pmid: 31359518

More than 70% of global food supply depends on seeds. The major seed reserves, such as proteins, lipids, and polysaccharides, are produced during seed maturation. Here, we report that DELAY OF GERMINATION 1‐LIKE 4 (DOGL4) is a major inducer of reserve accumulation during seed maturation. The DOGL family proteins are plant‐specific proteins of largely unknown biochemical function. DOGL4 shares only limited homology in amino acid sequence with DOG1, a major regulator of seed dormancy. DOGL4 was identified as one of the outstanding abscisic acid (ABA)‐induced genes in our RNA sequencing analysis, whereas DOG1 was not induced by ABA. Induction of DOGL4 caused the expression of 70 seed maturation‐specific genes, even in germinating seeds, including the major seed reserves ALBUMIN, CRUCIFERIN and OLEOSIN. Although DOG1 affects the expression of many seed maturation genes, the major seed reserve genes induced by DOGL4 are not altered by the dog1 mutation. Furthermore, the reduced dormancy and longevity phenotypes observed in the dog1 seeds were not observed in the dogl4 mutants, suggesting that these two genes have limited functional overlap. Taken together, these results suggest that DOGL4 is a central factor mediating reserve accumulation in seeds, and that the two DOG1 family proteins have diverged over the course of evolution into independent regulators of seed maturation, but retain some overlapping function.

Sun, Guangxin; Strebl, Michael; Merz, Maximilian; Blamberg, Robert; Huang, Fong‐Chin; McGraphery, Kate; Hoffmann, Thomas; Schwab, Wilfried

doi: 10.1111/tpj.14420pmid: 31124249

Enzyme promiscuity, a common property of many uridine diphosphate sugar‐dependent glycosyltransferases (UGTs) that convert small molecules, significantly hinders the identification of natural substrates and therefore the characterization of the physiological role of enzymes. In this paper we present a simple but effective strategy to identify endogenous substrates of plant UGTs using LC‐MS‐guided targeted glycoside analysis of transgenic plants. We successfully identified natural substrates of two promiscuous Nicotiana benthamiana UGTs (NbUGT73A24 and NbUGT73A25), orthologues of pathogen‐induced tobacco UGT (TOGT) from Nicotiana tabacum, which is involved in the hypersensitive reaction. While in N. tabacum, TOGT glucosylated scopoletin after treatment with salicylate, fungal elicitors and the tobacco mosaic virus, NbUGT73A24 and NbUGT73A25 produced glucosides of phytoalexin N‐feruloyl tyramine, which may strengthen cell walls to prevent the intrusion of pathogens, and flavonols after agroinfiltration of the corresponding genes in N. benthamiana. Enzymatic glucosylation of fractions of a physiological aglycone library confirmed the biological substrates of UGTs. In addition, overexpression of both genes in N. benthamiana produced clear lesions on the leaves and led to a significantly reduced content of pathogen‐induced plant metabolites such as phenylalanine and tryptophan. Our results revealed some additional biological functions of TOGT enzymes and indicated a multifunctional role of UGTs in plant resistance.

Rubio, Maria C.; Calvo‐Begueria, Laura; Díaz‐Mendoza, Mercedes; Elhiti, Mohamed; Moore, Marten; Matamoros, Manuel A.; James, Euan K.; Díaz, Isabel; Pérez‐Rontomé, Carmen; Villar, Irene; Sein‐Echaluce, Violeta C.; Hebelstrup, Kim H.; Dietz, Karl‐Josef; Becana, Manuel

Wu, Honghong; Shabala, Lana; Zhou, Meixue; Su, Nana; Wu, Qi; Ul‐Haq, Tanveer; Zhu, Juan; Mancuso, Stefano; Azzarello, Elisa; Shabala, Sergey

doi: 10.1111/tpj.14424pmid: 31148333

Soil salinity is a major constraint for the global agricultural production. For many decades, Na+ exclusion from uptake has been the key trait targeted in breeding programs; yet, no major breakthrough in creating salt‐tolerant germplasm was achieved. In this work, we have combined the microelectrode ion flux estimation (MIFE) technique for non‐invasive ion flux measurements with confocal fluorescence dye imaging technique to screen 45 accessions of barley to reveal the relative contribution of Na+ exclusion from the cytosol to the apoplast and its vacuolar sequestration in the root apex, for the overall salinity stress tolerance. We show that Na+/H+ antiporter‐mediated Na+ extrusion from the root plays a minor role in the overall salt tolerance in barley. At the same time, a strong and positive correlation was found between root vacuolar Na+ sequestration ability and the overall salt tolerance. The inability of salt‐sensitive genotypes to sequester Na+ in root vacuoles was in contrast to significantly higher expression levels of both HvNHX1 tonoplast Na+/H+ antiporters and HvVP1 H+‐pumps compared with tolerant genotypes. These data are interpreted as a failure of sensitive varieties to prevent Na+ back‐leak into the cytosol and existence of a futile Na+ cycle at the tonoplast. Taken together, our results demonstrated that root vacuolar Na+ sequestration but not exclusion from uptake played the main role in barley salinity tolerance, and suggested that the focus of the breeding programs should be shifted from targeting genes mediating Na+ exclusion from uptake by roots to more efficient root vacuolar Na+ sequestration.

Diehn, Till Arvid; Bienert, Manuela Désirée; Pommerrenig, Benjamin; Liu, Zhaojun; Spitzer, Christoph; Bernhardt, Nadine; Fuge, Jacqueline; Bieber, Annett; Richet, Nicolas; Chaumont, François; Bienert, Gerd Patrick

doi: 10.1111/tpj.14428pmid: 31148338

The sophisticated uptake and translocation regulation of the essential element boron (B) in plants is ensured by two transmembrane transporter families: the Nodulin26‐like Intrinsic Protein (NIP) and BOR transporter family. Though the agriculturally important crop Brassica napus is highly sensitive to B deficiency, and NIPs and BORs have been suggested to be responsible for B efficiency in this species, functional information of these transporter subfamilies is extremely rare. Here, we molecularly characterized the NIP and BOR1 transporter family in the European winter‐type cv. Darmor‐PBY018. Our transport assays in the heterologous oocyte and yeast expression systems as well as in growth complementation assays in planta demonstrated B transport activity of NIP5, NIP6, NIP7 and BOR1 isoforms. Moreover, we provided functional and quantitative evidence that also members of the NIP2, NIP3 and NIP4 groups facilitate the transport of B. A detailed B‐ and tissue‐dependent B‐transporter expression map was generated by quantitative polymerase chain reaction. We showed that NIP5 isoforms are highly upregulated under B‐deficient conditions in roots, but also in shoot tissues. Moreover, we detected transcripts of several B‐permeable NIPs from various groups in floral tissues that contribute to the B distribution within the highly B deficiency‐sensitive flowers.

Baison, John; Vidalis, Amaryllis; Zhou, Linghua; Chen, Zhi‐Qiang; Li, Zitong; Sillanpää, Mikko J.; Bernhardsson, Carolina; Scofield, Douglas; Forsberg, Nils; Grahn, Thomas; Olsson, Lars; Karlsson, Bo; Wu, Harry; Ingvarsson, Pär K.; Lundqvist, Sven‐Olof;

Huang, Fei; Yuan, Wenya; Tian, Shu; Zheng, Qijie; He, Yuehui

doi: 10.1111/tpj.14430pmid: 31168864

Day length or photoperiod changes are crucial for plants to align the timing of the floral transition with seasonal changes. Through the photoperiod pathway, day length changes induce the expression of the florigenic FLOWERING LOCUS T (FT) to promote flowering. In the facultative long days (LDs) plant Arabidopsis thaliana, LD signals induce flowering, whereas short days (SDs) inhibit flowering. Here, we show that in Arabidopsis SIN3 LIKE (SNL) family genes, encoding a scaffold protein for assembly of histone deacetylase complexes, directly repress the expression of an FT activator and three FT repressors to regulate the transition to flowering in SDs and LDs, respectively. Under inductive LDs, SNLs including SIN3 LIKE 1 (SNL1) to SNL5, function in partial redundancy to repress the expression of three AP2 family transcription factors that repress FT expression, and therefore mediate LD induction of FT expression and promote the transition to flowering. In contrast, under non‐inductive SDs SNLs act to inhibit the floral transition, partly through direct repression of a MADS box transcriptional factor that promotes FT expression. Therefore, our results reveal that SNLs, through histone deacetylation, play a dual role for the control of flowering in the LD plant Arabidopsis: inhibiting flowering when the day length is shorter and promoting the floral transition when days become longer than a threshold length.

Zhan, Wei; Liu, Jie; Pan, Qingchun; Wang, Hong; Yan, Shijuan; Li, Kun; Deng, Min; Li, Wenqiang; Liu, Nannan; Kong, Qian; Fernie, Alisdair R.; Yan, Jianbing

doi: 10.1111/tpj.14432pmid: