Explore the vast range of titles available.

Lipid research represents a frontier for microbiology, as showcased by hopanoid lipids. Hopanoids, which resemble sterols and are found in the membranes of diverse bacteria, have left an extensive molecular fossil record. They were first discovered by petroleum geologists. Today, hopanoid-producing bacteria remain abundant in various ecosystems, such as the rhizosphere. Recently, great progress has been made in our understanding of hopanoid biosynthesis, facilitated in part by technical advances in lipid identification and quantification. A variety of genetically tractable, hopanoid-producing bacteria have been cultured, and tools to manipulate hopanoid biosynthesis and detect hopanoids are improving. However, we still have much to learn regarding how hopanoid production is regulated, how hopanoids act biophysically and biochemically, and how their production affects bacterial interactions with other organisms, such as plants. The study of hopanoids thus offers rich opportunities for discovery.

This article explores the issues surrounding the agroecological transition in the European wine industry, focusing on reducing pesticide use, developing organic certification and using genetic research in relation to resistant grape varieties. The study distinguishes between stakeholders from the wine industry, institutions and the agricultural research sector. The findings consistently identify the agroecological transition as a priority, particularly in terms of pesticide reduction. However, variations exist in the views of the surveyed stakeholders. French and Portuguese stakeholders emphasise the role of market and societal pressures as drivers of the transition, while Italian producers do not. Professionals in France and Portugal express doubts about achieving pesticide reduction through changes in practices, while others stress the importance of regulatory constraints. The research also highlights industry challenges such as decreased consumption due to health awareness and the need for social responsibility. Resistant grape varieties are seen as a viable solution, especially for the development of organic production, but market acceptability remains a significant hurdle. The study sheds light on stakeholder perspectives and challenges, thus contributing to a better understanding of priorities in the European wine industry’s pursuit of sustainable practices.

Legume plants form a root-nodule symbiosis with rhizobia. This symbiosis establishment generally relies on rhizobium-produced Nod factors (NFs) and their perception by leguminous receptors (NFRs) that trigger nodulation. However, certain rhizobia hijack leguminous nodulation signalling via their type III secretion system, which functions in pathogenic bacteria to deliver effector proteins into host cells. Here, we report that rhizobia use pathogenic-like effectors to hijack legume nodulation signalling. The rhizobial effector Bel2-5 resembles the XopD effector of the plant pathogen Xanthomonas campestris and could induce nitrogen-fixing nodules on soybean nfr mutant. The soybean root transcriptome revealed that Bel2-5 induces expression of cytokinin-related genes, which are important for nodule organogenesis and represses ethylene- and defense-related genes that are deleterious to nodulation. Remarkably, Bel2-5 introduction into a strain unable to nodulate soybean mutant affected in NF perception conferred nodulation ability. Our findings show that rhizobia employ and have customized pathogenic effectors to promote leguminous nodulation signalling.

Bradyrhizobium sp. DOA9 can nodulate a wide spectrum of legumes; however, unlike other bradyrhizobia, DOA9 carries a symbiotic plasmid harboring type III secretion system (T3SS) and several effector (T3E) genes, one of which encodes a putative type III effector SkP48. Here, we demonstrated the pivotal roles of SkP48 from Bradyrhizobium sp. DOA9 in inhibiting nodulation of various Vigna species and Crotalaria juncea and suppressing nodulation efficiency of Arachis hypogaea . By contrast, the nodulation efficiency of a SkP48 mutant did not differ significantly with the DOA9 wild-type strain on Macroptilium atropurpureum and Stylosanthes hamata . The SUMO domain of SkP48 is primarily responsible for the blocking nodulation phenotype V. radiata . An evolutionary analysis revealed that the SkP48 which contains a shikimate kinase and a SUMO protease (C48 cysteine peptidase) domain, SkP48 is distinct from other effectors previously reported in other bradyrhizobia and pathogenic bacteria. Our findings suggest that the putative T3E SkP48 is a key factor suppressing nodulation and nodule organogenesis in several legumes by activation of effector-triggered immunity through salicylic acid biosynthesis induction, which is deleterious to rhizobial infection. In addition, nodulation may be modulated by the function of defensins involved in jasmonic acid signalling in V. radiata SUT1.

Effector proteins secreted via the type III secretion system (T3SS) of nitrogen-fixing rhizobia are key determinants of symbiotic compatibility in legumes. Previous report revealed that the T3SS of Bradyrhizobium sp. DOA9 plays negative effects on Arachis hypogaea symbiosis. In this study, we characterized the symbiotic role of 4 effector proteins (p0490, p0871, SkP48, and p0903) containing the small ubiquitin-like modifier (SUMO) protease domain identified in DOA9 during symbiosis. While the DOA9 strain and the two mutants of SUMO-proteases, p0490 and p0871, induced inefficient nodulation in A. hypogaea, the mutation of SUMO-proteases SkP48 or p0903 promoted efficient symbiosis comparable to the type strain Bradyrhizobium arachidis CCBAU051107. Complementation study of ∆p0903 with various mutated forms of p0903 highlighted importance of ubiquitin-like protein (ULP) domain in restriction of nodulation in A. hypogaea. We observed the accumulation of jasmonic acid (JA) and upregulation of several defence genes involved in the JA/ethylene (ET) signalling pathway at the early stage of infection in roots inoculated with DOA9 strain compared with those inoculated with the DOA9-∆p0903 strain. Our data highlight the importance of SUMO-protease effectors during the symbiotic interaction between bradyrhizobia and A. hypogaea, which could be useful for the development of high-performance inocula to improve its growth. Keywords Bradyrhizobium sp, Arachis hypogaea, T3SS, and SUMO-proteaseThe symbiotic relationship between rhizobia and legumes represents a fascinating and complex biological process with significant agronomical and ecological importance. This interaction begins when nitrogen-fixing rhizobia release signalling molecules called Nod factors (NFs), which trigger the formation of root nodules and facilitate bacterial infection. Within these nodules, rhizobia convert atmospheric nitrogen into a plant-accessible form in exchange for photosynthates and other nutrients from the host plant. Among rhizobia, Bradyrhizobium strains are particularly valuable in agriculture because of their ability to form symbioses with economically important legume crops such as soybeans, peanuts, and cowpeas 1-3 . This mutually beneficial partnership has attracted considerable scientific interest, as it plays a crucial role in sustainable agriculture and global nitrogen cycling.In several strains of Bradyrhizobium, a type III secretion system (T3SS) plays a crucial role during symbiosis, significantly influencing the interaction with host plants 4,5 . The T3SS serves as a nanosyringe structure found in Gram-negative bacteria. Its function is to deliver type III effectors (T3Es) into eukaryotic host cells during interaction with the host 6 . As observed in pathogenic bacteria, the T3Es identified in rhizobia, often referred to as nodulation outer proteins (Nops), can act as double-edged swords, depending on the host plant 7 . They can promote symbiosis by suppressing the plant's immune system; however, if recognized by plant resistance proteins, they can trigger an immune response known as effector-triggered immunity (ETI), which can block

Nitrogen fixation in the legume-rhizobium symbiosis is a crucial area of research for more sustainable agriculture. Our knowledge of the plant cascade in response to the perception of bacterial Nod factors has increased in recent years. However, the discovery that Nod factors are not involved in the Aeschynomene-Bradyrhizobium spp. interaction suggests that alternative molecular dialogues may exist in the legume family. We evaluated the conservation of the signaling pathway common to other endosymbioses using three candidate genes: Ca(2+)/Calmodulin-Dependent Kinase (CCaMK), which plays a central role in cross signaling between nodule organogenesis and infection processes; and Symbiosis Receptor Kinase (SYMRK) and Histidine Kinase1 (HK1), which act upstream and downstream of CCaMK, respectively. We showed that CCaMK, SYMRK, and HK1 are required for efficient nodulation in Aeschynomene evenia. Our results demonstrate that CCaMK and SYMRK are recruited in Nod factor-independent symbiosis and, hence, may be conserved in all vascular plant endosymbioses described so far.

The Bradyrhizobium vignae strain ORS3257 is an elite strain recommended for cowpea inoculation in Senegal. This strain was recently shown to establish symbioses on some Aeschynomene species using a cocktail of Type III effectors (T3Es) secreted by the T3SS machinery. In this study, using a collection of mutants in different T3Es genes, we sought to identify the effectors that modulate the symbiotic properties of ORS3257 in three Vigna species ( V. unguiculata , V. radiata and V. mungo ). While the T3SS had a positive impact on the symbiotic efficiency of the strain in V. unguiculata and V. mungo , it blocked symbiosis with V. radiata . The combination of effectors promoting nodulation in V. unguiculata and V. mungo differed, in both cases, NopT and NopAB were involved, suggesting they are key determinants for nodulation, and to a lesser extent, NopM1 and NopP1, which are additionally required for optimal symbiosis with V. mungo . In contrast, only one effector, NopP2, was identified as the cause of the incompatibility between ORS3257 and V. radiata . The identification of key effectors which promote symbiotic efficiency or render the interaction incompatible is important for the development of inoculation strategies to improve the growth of Vigna species cultivated in Africa and Asia.

In many countries, the consumption of still wine is in strong decline. The market for rose wine, however, stands in stark contrast to this trend, seeing worldwide growth of almost 30% over the last 15 years. For most observers/experts, product colour plays an important role in this paradigm shift. For this reason, companies’ marketing efforts often focus on this purely visual characteristic. There is, however, no certainty that other emerging consumer demands, related to environmental concerns or how “natural” a wine is (organic wines, natural wines, etc.), do not also play a role in the enthusiasm seen in new wine consumers. This article proposes an assessment of expectations related to colour and the decisions made by rose wine consumers, using two complementary experiments carried out in France. The first experiment is based on an online survey studying only consumers’ colour preferences. We will show that, contrary to popular belief, there is no consensus on this criterion, although regional trends can be identified. Typically, the “salmon” shade, which is generally the leader on the global market—and characteristic of Provence wines—does not win unanimous support across all regions. In contrast, an “apricot” shade seems to be preferred by consumers in the Bordeaux region. The second experiment confirms this result within the framework of an experimental market revealing consumers’ willingness to pay (WTP). This market also offers consumers the opportunity to taste wines and provides information on organic certification and “naturalness” (symbolised by the absence of added sulphites). We will then demonstrate how the latter criteria, although often popular, play only a small role—compared with colour—in consumer decisions. We will conclude this article with observations on the atypical nature of the rose wine market and on possible avenues for further research related to the emotional role colour plays in wine tasting and its possible specificity in the world of food and drink products.

Many Proteobacteria possess LuxI-LuxR-type quorum-sensing systems that produce and detect fatty acyl-homoserine lactone (HSL) signals. The photoheterotroph Rhodopseudomonas palustris is unusual in that it produces and detects an aryl-HSL, p-coumaroyl-HSL, and signal production requires an exogenous source of p-coumarate. A photosynthetic stem-nodulating member of the genus Bradyrhizobium produces a small molecule signal that elicits an R. palustris quorum-sensing response. Here, we show that this signal is cinnamoyl-HSL and that cinnamoyl-HSL is produced by the LuxI homolog BraI and detected by BraR. Cinnamoyl-HSL reaches concentrations on the order of 50 nM in cultures of stem-nodulating bradyrhizobia grown in the presence or absence of cinnamate. Acyl-HSLs often reach concentrations of 0.1-30 mu M in bacterial cultures, and generally, LuxR-type receptors respond to signals in a concentration range from 5 to a few hundred nanomolar. Our stem-nodulating Bradyrhizobium strain responds to picomolar concentrations of cinnamoyl-HSL and thus, produces cinnamoyl-HSL in excess of the levels required for a signal response without an exogenous source of cinnamate. The ability of Bradyrhizobium to produce and respond to cinnamoyl-HSL shows that aryl-HSL production is not unique to R. palustris, that the aromatic acid substrate for aryl-HSL synthesis does not have to be supplied exogenously, and that some acyl-HSL quorum-sensing systems may function at very low signal production and response levels.

Abstract The Bradyrhizobium sp. strain ORS285 is able to establish a nitrogen-fixing symbiosis with both Nod factor (NF) dependent and NF-independent Aeschynomene species. Here, we have studied the growth characteristics and symbiotic interaction of a glutamate synthase (GOGAT; gltD::Tn5 ) mutant of Bradyrhizobium ORS285. We show that the ORS285 gltD::Tn5 mutant is unable to use ammonium, nitrate and many amino acids as nitrogen source for growth and is unable to fix nitrogen under free-living conditions. Moreover, on several nitrogen sources, the growth rate of the gltB::Tn5 mutant was faster and/or the production of the carotenoid spirilloxanthin was much higher as compared to the wild-type strain. The absence of GOGAT activity has a drastic impact on the symbiotic interaction with NF-independent Aeschynomene species. With these species, inoculation with the ORS285 gltD::Tn5 mutant does not result in the formation of nodules. In contrast, the ORS285 gltD::Tn5 mutant is capable to induce nodules on NF-dependent Aeschynomene species, but these nodules were ineffective for nitrogen fixation. Interestingly, in NF-dependent and NF-independent Aeschynomene species inoculation with the ORS285 gltD::Tn5 mutant results in browning of the plant tissue at the site of the infection suggesting that the mutant bacteria induce plant defence responses.