Evaluation of Thellungiella halophila ST7 for improving salt tolerance in cotton

Background: Gossypium hirsutum(upland cotton) is one of the principal fiber crops in the world. Cotton yield is highly affected by abiotic stresses, among which salt stress is considered as a major problem around the globe. Transgenic approach is efficient to improve cotton salt tolerance but depending on the availability of salt tolerance genes.Results: In this study we evaluated salt tolerance candidate gene ST7 from Thellungiella halophila, encoding a homolog of Arabidopsis aluminum-induced protein, in cotton. Our results showed that ThST7 overexpression in cotton improved germination under NaCl stress as well as seedling growth. Our field trials also showed that ThST7 transgenic cotton lines produced higher yield under salt stress conditions. The improved salt tolerance of the transgenic cotton lines was partially contributed by enhanced antioxidation as shown by diaminobenzidine(DAB) and nitrotetrazolium blue chloride(NBT) staining. Moreover, transcriptomic analysis of ThST7 overexpression lines showed a significant upregulation of the genes involved in ion homeostasis and antioxidation, consistent with the salt tolerance phenotype of the transgenic cotton.Conclusions: Our results demonstrate that ThST7 has the ability to improve salt tolerance in cotton. The ThST7 transgenic cotton may be used in cotton breeding for salt tolerance cultivars.

Functional characterization,structural basis,and protein engineering of a rare flavonoid 2′-O-glycosyltransferase from Scutellaria baicalensis

Glycosylation is an important post-modification reaction in plant secondary metabolism,and contributes to structural diversity of bioactive natural products.In plants,glycosylation is usually catalyzed by UDP-glycosyltransferases.Flavonoid 2′-O-glycosides are rare glycosides.However,no UGTs have been reported,thus far,to specifically catalyze 2′-O-glycosylation of flavonoids.In this work,UGT71AP2 was identified from the medicinal plant Scutellaria baicalensis as the first flavonoid 2′-O-glycosyltransferase.It could preferentially transfer a glycosyl moiety to 2′-hydroxy of at least nine flavonoids to yield six new compounds.Some of the 2′-O-glycosides showed noticeable inhibitory activities against cyclooxygenase 2.The crystal structure of UGT71AP2(2.15Å)was solved,and mechanisms of its regio-selectivity was interpreted by pKa calculations,molecular docking,MD simulation,MM/GBSA binding free energy,QM/MM,and hydrogen‒deuterium exchange mass spectrometry analysis.Through structure-guided rational design,we obtained the L138T/V179D/M180T mutant with remarkably enhanced regio-selectivity(the ratio of 7-O-glycosylation byproducts decreased from 48%to 4%)and catalytic efficiency of 2′-O-glycosylation(kcat/Km,0.23 L/(s·μmol),12-fold higher than the native).Moreover,UGT71AP2 also possesses moderate UDP-dependent de-glycosylation activity,and is a dual function glycosyltransferase.This work provides an efficient biocatalyst and sets a good example for protein engineering to optimize enzyme catalytic features through rational design.

Knockout of OsSPL10 confers enhanced glufosinate resistance in rice

Dear Editor,Rice(Oryza sativa L.)is one of the world’s major food crops,feeding more than half of the global population.To reduce labor and production costs,direct seeding is becoming popular for rice cultivation,but weeds have become a serious problem(Jin et al.,2022).Chemical herbicides are one of the most effective ways to control weeds.Therefore,the development of herbicide-resistant rice has great significance for modern rice production.

Corrigendum to“Root-derived long-distance signals trigger ABA synthesis and enhance drought resistance in Arabidopsis”[Journal of Genetics and Genomics(2024)51,749e761]

This corrigendum clarifies to supplement the“Data availability”session.Data availability The raw sequence data reported in this paper have been deposited in the National Genomics Data Center,China National Center for Bioinformation/Beijing Institute of Genomics,Chinese Academy of Sciences(GSA:CRA017487 and iProx:IPX0009175000).

The concerted actions of Tipl/CLIP-170, Klp5/Kinesin-8, and Alpl4/XMAP215 regulate microtubule catastrophe at the cell end

Spatial regulation of microtubule catastrophe is important for controlling microtubule length and consequently contributes to the proper establishment of cell polarity and cell growth.The+TIP proteins including Tipl/CLIP-170,Klp5/Kinesin-8,and Alpl4/XMAP215 reside at microtubule plus ends to regulate microtubule dynamics.In the fission yeast Schizosaccharomyces pombe,Tipi and Alpl4 serve as microtubule-stabilizing factors,while Klp5 functions oppositely as a catastrophe-promoting factor.Despite that Tipi has been shown to play a key role in restricting microtubule catastrophe to the cell end,how Tipi fulfills the role remains to be determined.Employing live-cell microscopy,we showed that the absence of Tip i impairs the localization of both Klp5 and Alpl4 at microtubule plus ends,but the absence of Klp5 prolongs the residence time of Tipi at microtubule plus ends.We further revealed that Klp5 accumulates behind Tip i at microtubule plus ends in a Tipl-dependent manner.In addition,artificially tethering Klp5 to microtubule plus ends promotes premature microtubule catastrophe,while tethering Alpl4 to microtubule plus ends in the cells lacking Tipi rescues the phenotype of short microtubules.These findings establish that Tipi restricts microtubule catastrophe to the cell end likely by spatially restricting the microtubule catastrophe activity of Klp5 and stabilizing Alpl4 at microtubule plus ends.Thus,the work demonstrates the orchestration of Tipi,Alpl4,and Klp5 in ensuring microtubule catastrophe at the cell end.

Thellungiella halophila ST103 enhances salt tolerance in Gossypium hirsutum

Background:Cotton(Gossypium hirsutum),the major textile fiber crop ofthe world,is negatively affected by salinity.It leads to the induction of adverse effects on growth and development of cott on.The overall yield of cotton faces major drawback once they are grown in saline soil.To improve cotton salt tolerance,tunsgenic approach offers a fast and effective way but it relies on the availability of salt tolerance genes.Results:In this study,we have reported the evaluation of ThST103,a homologue of Arabidopsis ozone-induced protein(AtOZI1)in Thellungiellahalophila,in enhancing salt tolerance in cotton.Overexpression ofThST103 enabled cotton plants to germinate and grow better than the wild types under salt stress.The transgenic lines showed enhanced survival rate in the saline environment and experienced less oxidative damage compared with the wild types.In the field,the transgenic cotton lines produced higher yield than the wild type in saline soil.Transcriptomic comparison analyses of ThST103 overexpression lines versus the wild type revealed upregulated genes enriched in salt stress tolerance and ion homeostasis.Conclusions:Our results dem on strate that ThST103 has the capability to improve salt tolerance in cotton.It can be used in cotton breeding for salt tolerance cultivars.

Arabidopsis NLP7 improves nitrogen use efficiency and yield in cotton

Background: Nitrogen(N) is a required macronutrient for cotton growth and productivity. Excessive N fertilizers are applied in agriculture for crop yield maximization, which also generates environmental pollution. Improving crop N use efficiency(NUE) is the most economical and desirable way of reducing fertilizer application and environmental pollution. NUE has been an important issue in cotton. So far there is no report on cotton NUE improvement via transgenic approach. Nin-like proteins(NLP) are transcription factors regulating NUE. We previously demonstrated that At NLP7 improved NUE and biomass when overexpressed in Arabidopsis. However, it is not known whether At NLP7 can be used to improve NUE in crops.Results: To test the feasibility, we expressed At NLP7 in cotton and evaluated NUE and yield of the transgenic cotton in the field. Transgenic cotton showed improved NUE and yield under both low and high N conditions. In addition, plant biomass, amount of absorbed N, N contents, activities of N-assimilating enzymes, and the expression of N-related marker genes were significantly increased in transgenic cotton compared with the wild type control, suggesting that At NLP7 enhances NUE in cotton.Conclusion: Together, our results demonstrate that At NLP7 is a promising candidate to improve NUE and yield in cotton.

Loss of OsARF18 function confers glufosinate resistance in rice

Dear Editor,Weeds are one of the most common biotic stresses causing severe crop yield decline(Jin et al.,2022).Chemical herbicides are an economical and effective method for weed control and are widely used in modern agriculture(Amna et al.,2019).However,the improper use of herbicides can impede crop growth,ultimately leading to reduced crop yields.Therefore,it is of great significance to develop herbicide-resistant crops to alleviate weed infestations and maintain sustainable crop production.

Root-derived long-distance signals trigger ABA synthesis and enhance drought resistance in Arabidopsis

Vascular plants have evolved intricate long-distance signaling mechanisms to cope with environmental stress,with reactive oxygen species(ROS)emerging as pivotal systemic signals in plant stress responses.However,the exact role of ROS as root-to-shoot signals in the drought response has not been determined.In this study,we reveal that compared with wild-type plants,ferric reductase defective 3(frd3)mutants exhibit enhanced drought resistance concomitant with elevated NINE-CIS-EPOXYCAROTENOID DIOXYGENASE 3(NCED3)transcript levels and abscisic acid(ABA)contents in leaves as well as increased hydrogen peroxide(H_(2)O_(2))levels in roots and leaves.Grafting experiments distinctly illustrate that drought resistance can be conferred by the frd3 rootstock regardless of the scion genotype,indicating that long-distance signals originating from frd3 roots promote an increase in ABA levels in leaves.Intriguingly,the drought resistance conferred by the frd3 mutant rootstock is weakened by the CAT2-overexpressing scion,suggesting that H_(2)O_(2)may be involved in long-distance signaling.Moreover,the results of comparative transcriptome and proteome analyses support the drought resistance phenotype of the frd3 mutant.Taken together,our findings substantiate the notion that frd3 root-derived long-distance signals trigger ABA synthesis in leaves and enhance drought resistance,providing new evidence for root-to-shoot long-distance signaling in the drought response of plants.

OsNLP3 enhances grain weight and reduces grain chalkiness in rice

Grain weight,a key determinant of yield in rice(Oryza sativa L.),is governed primarily by genetic factors,whereas grain chalkiness,a detriment to grain quality,is intertwined with environmental factors such as mineral nutrients.Nitrogen(N)is recognized for its effect on grain chalkiness,but the underlying molecular mechanisms remain to be clarified.This study revealed the pivotal role of rice NODULE INCEPTION-LIKE PROTEIN 3(OsNLP3)in simultaneously regulating grain weight and grain chalkiness.Our investigation showed that loss of OsNLP3 leads to a reduction in both grain weight and dimension,in contrast to the enhancement observed with OsNLP3 overexpression.OsNLP3 directly suppresses the expression of OsCEP6.1 and OsNF-YA8,which were identified as negative regulators associated with grain weight.Consequently,two novel regulatory modules,OsNLP3-OsCEP6.1 and OsNLP3-OsNF-YA8,were identified as key players in grain weight regulation.Notably,the OsNLP3-OsNF-YA8 module not only increases grain weight but also mitigates grain chalkiness in response to N.This research clarifies the molecular mechanisms that orchestrate grain weight through the OsNLP3-OsCEP6.1 and OsNLP3-OsNF-YA8 modules,highlighting the pivotal role of the OsNLP3-OsNF-YA8 module in alleviating grain chalkiness.These findings reveal potential targets for simultaneous enhancement of rice yield and quality.

The innovative safe herbicide dienediamine saves paraquat

Throughout the history of agriculture,the challenge of weed management has endured,necessitating significant investments to facilitate ideal crop growth and maximize yields.Strategies for weed control mainly involve manual and chemical methodologies.While manual weeding persists in certain regions,chemical herbicides notably represent the primary approach.

A gain-of-function mutation of the MATE family transporter DTX6 confers paraquat resistance in Arabidopsis

Paraquat is one of the most widely used nonselective herbicides and has elicited the emergence of para-quat-resistant weeds.However,the molecular mechanisms of paraquat resistance are not completely un-derstood.Here we report the Arabidopsis gain-of-function mutant pqt15-D with significantly enhanced resistance to paraquat and the corresponding gene PQT15,which encodes the Multidrug and Toxic Extru-sion(MATE)transporter DTX6.A point mutation at+932 bp in DTX6 causes a G311E amino acid substitution,enhancing the paraquat resistance ofpqt15-D,and overexpression of DTX6/PQT15 in the wild-type plants also results in strong paraquat resistance.Moreover,heterologous expression of DTX6 and DTX6-D in Es-cherichia coil significantly enhances bacterial resistance to paraquat.Importantly,overexpression of DTX6-D enables Arabidopsis plants to tolerate 4 mM paraquat,a near-commercial application level.DTX6/PQT15 is localized in the plasma membrane and endomembrane,and functions as a paraquat efflux transporter as demonstrated by paraquat efflux assays with isolated protoplasts and bacterial cells.Taken together,our results demonstrate that DTX6/PQT15 is an efflux transporter that confers paraquat resis-tance by exporting paraquat out of the cytosol.These findings reveal a molecular mechanism of paraquat resistance in higher plants and provide a promising candidate gene for engineering paraquat-resistant crops.

Action mode of NPA:direct inhibition on PIN auxin transporters

Chemical tools play essential roles in dissecting the molecular mechanisms underlying biological processes in living systems.In the history of plant biology,N-1-naphthylphthalamic acid(NPA)has long been used as an auxin export inhibitor,and multiple in vivo targets have been proposed,such as ABC transporters,TWISTED DWARF1,and BIG/-rlR3(reviewed in Teale and Palme,2018).These proteins exhibit pleiotropic functions,which were proposed to indirectly mediate the NPA effect through the activity or trafficking of PIN-FORMED(PIN)auxin transporters.However,the debate on the pure target of N PA often makes a clear interpretation of such experimental data elusive.

Understanding paraquat resistance mechanisms in Arabidopsis thaliana to facilitate the development of paraquat-resistant crops

Paraquat(PQ)is the third most used broad-spectrum nonselective herbicide around the globe after glyphosate and glufosinate.Repeated usage and overreliance on this herbicide have resulted in the emergence of PQ-resistant weeds that are a potential hazard to agriculture.It is generally believed that PQ resistance in weeds is due to increased sequestration of the herbicide and its decreased translocation to the target site,as well as an enhanced ability to scavenge reactive oxygen species.However,little is known about the genetic bases and molecular mechanisms of PQ resistance in weeds,and hence no PQ-resistant crops have been developed to date.Forward genetics of the model plant Arabidopsis thaliana has advanced our understanding of the molecular mechanisms of PQ resistance.This review focuses on PQ resistance loci and resistance mechanisms revealed in Arabidopsis and examines the possibility of developing PQ-resistant crops using the elucidated mechanisms.

Pollen hydration:A tale of two peptides

Massive amount of different pollen could be landed on the stigma of any given angiosperm species,but only compatible pollen can be allowed to germinate on this particular stigma.Once germinated,pollen starts its long journey by penetrating the stigmatic surface,coming across the style,going through the transmitting tract,turning on the funiculus,and finally reaching the embryo sac,where the pollen tube releases its cargo,two sperm cells,to fuse with two female gametes,the egg cell and the central cell,respectively(Johnson et al.,2017;Kim et al.t 2021).This fascinating and intricate adventure all starts with pollen hydration,but how the stigma is prepared and reacts to accept the compatible pollen to facilitate pollen hydration has long been a mystery.

TMK:A crucial piece of the acid growth puzzle

Plant cells have relatively high turgor pressure driving cell expan-sion,which is restricted by the cell wall.How plant cells grow in an intrinsically controlled manner is an intriguing question,and the phytohormone auxin(indole-3-acetic acid,IAA)plays a vital reg-ulatory role.The auxin-mediated acid growth theory was pro-posed decades ago,whereas the underlying mechanisms were not fully elucidated.Plasma membrane(PM)H+-ATPases,also called Arabidopsis AUTOINHIBITED H+ATPASEs(AHAs),are proton pumps majorly responsible for regulating cell growth in plants.Based on our current understandings of the acid growth theory,auxin stimulates AHA proteins and thus promotes proton(H+)efflux,which thereby acidifies the apoplast to activate cell wall-modifying enzymes,such as expansins,eventually softening the cell wall to accommodate cell expansion(Duet al.,2020).Activated AHA proteins also cause PM hyperpolarization,enabling solute and water uptake to increase turgor pressure driving cell expansion(Duet al.,2020).Hence,how auxin activates PM H^(+)-ATPases is central to the acid growth theory.However,that was until now not fully understood.

Balanced nitrogen–iron sufficiency boosts grain yield and nitrogen use efficiency by promoting tillering

Crop yield plays a critical role in global food security.For optimal plant growth and maximal crop yields,nutrients must be balanced.However,the potential significance of balanced nitrogen-iron(N-Fe)for improving crop yield and nitrogen use efficiency(NUE)has not previously been addressed.Here,we show that balanced N-Fe sufficiency significantly increases tiller number and boosts yield and NUE in rice and wheat.NIN-like protein 4(OsNLP4)plays a pivotal role in maintaining the N-Fe balance by coordinately regulating the expression of multiple genes involved in N and Fe metabolism and signaling.OsNLP4 also suppresses OsD3 expression and strigolactone(SL)signaling,thereby promoting tillering.Balanced N-Fe sufficiency promotes the nuclear localization of OsNLP4 by reducing H_(2)O_(2) levels,reinforcing the functions of OsNLP4.Interestingly,we found that OsNLP4 upregulates the expression of a set of H2O2-scavenging genes to promote its own accumulation in the nucleus.Furthermore,we demonstrated that foliar spraying of balanced N-Fe fertilizer at the tillering stage can effectively increase tiller number,yield,and NUE of both rice and wheat in the field.Collectively,these findings reveal the previously unrecognized effects of N-Fe balance on grain yield and NUE as well as the molecular mechanism by which the OsNLP4-OsD3 module integrates N-Fe nutrient signals to downregulate SL signaling and thereby promote rice tillering.Our study sheds light on how N-Fe nutrient signals modulate rice tillering and provide potential innovative approaches that improve crop yield with reduced N fertilizer input for benefitting sustainable agriculture worldwide.

Nitrate-responsive OsMADS27 promotes salt tolerance in rice

Salt stress is a major constraint on plant growth and yield.Nitrogen(N)fertilizers are known to alleviate salt stress.However,the underlying molecular mechanisms remain unclear.Here,we show that nitratedependent salt tolerance is mediated by OsMADS27 in rice.The expression of OsMADS27 is specifically induced by nitrate.The salt-inducible expression of OsMADS27 is also nitrate dependent.OsMADS27 knockout mutants are more sensitive to salt stress than the wild type,whereas OsMADS27 overexpression lines are more tolerant.Transcriptomic analyses revealed that OsMADS27 upregulates the expression of a number of known stress-responsive genes as well as those involved in ion homeostasis and antioxidation.We demonstrate that OsMADS27 directly binds to the promoters of OsHKT1.1 and OsSPL7 to regulate their expression.Notably,OsMADS27-mediated salt tolerance is nitrate dependent and positively correlated with nitrate concentration.Our results reveal the role of nitrate-responsive OsMADS27 and its downstream target genes in salt tolerance,providing a molecular mechanism for the enhancement of salt tolerance by nitrogen fertilizers in rice.OsMADS27 overexpression increased grain yield under salt stress in the presence of sufficient nitrate,suggestingthatOsMADS27 is a promising candidate for the improvementof salt tolerance inrice.

Changing Gly311 to an acidic amino acid in the MATE family protein DTX6 enhances Arabidopsis resistance to the dihydropyridine herbicides

In modern agriculture,frequent application of herbicides may induce the evolution of resistance in plants,but the mechanisms underlying herbicide resistance remain largely unexplored.Here,we report the char-acterization of rtp 1(resistant to paraquat 1),an Arabidopsis mutant showing strong resistance to the widely used herbicides paraquat and diquat.The rtp1 mutant is semi-dominant and carries a point mutation in the gene encoding the multidrug and toxic compound extrusion family protein DTX6,leading to the change of glycine to glutamic acid at residue 311(G311E).The wild-type DTX6 with glycine 311 conferred weak para-quat and diquat resistance when overexpressed,while mutation of glycine 311 to a negatively charged amino acid(G311E or G311D)markedly increased the paraquat and diquat resistance of plants,whereas mutation to a positively charged amino acid(G311R or G311K)compromised the resistance,suggesting that the charge property of residue 311 of DTX6 is critical for the paraquat and diquat resistance of Arabi-dopsis plants.DTX6 is localized in the endomembrane trafficking system and may undergo the endosomal sorting to localize to the vacuole and plasma membrane.Treatment with the V-ATPase inhibitor ConA reduced the paraquat resistance of the rtp1 mutant.Paraquat release and uptake assays demonstrated that DTX6 is involved in both exocytosis and vacuolar sequestration of paraquat.DTX6 and DTX5 show functional redundancy as the dtx5 dtx6 double mutant but not the dtx6 single mutant plants were more sen-sitive to paraquat and diquat than the wild-type plants.Collectively,our work reveals a potential mecha-nism for the evolution of herbicide resistance in weeds and provides a promising gene for the manipulation of plant herbicide resistance.

AtPQT11,a P450 enzyme,detoxifies paraquat via N-demethylation

Paraquat(1,1’-dimethyl-4,4’-bipyridinium dichloride,PQ)has been widely used as a broad spectrum nonselective herbicide in agriculture for decades(Baldwin et al.,1968).Plants absorb PQ from their environment and transport to the chloroplasts,the site of its action where it competes for electrons from photosystem I(PSI)and cyclically generates superoxide that is converted to H2O2by superoxide dismutases(SODs),resultantly accumulating a large amount of reactive oxygen species(ROS)and thereby killing plants(Farrington et al.,1973).