New Phytologist最新文献

Symbiotic nitrogen fixation carried out by the interaction between legumes and rhizobia is the main source of nitrogen in natural ecosystems and in sustainable agriculture. For the symbiosis to be viable, nutrient exchange between the partners is essential. Transition metals are among the nutrients delivered to the nitrogen-fixing bacteria within the legume root nodule cells. These elements are used as cofactors for many of the enzymes controlling nodule development and function, including nitrogenase, the only known enzyme able to convert N₂ into NH₃. In this review, we discuss the current knowledge on how iron, zinc, copper, and molybdenum reach the nodules, how they are delivered to nodule cells, and how they are transferred to nitrogen-fixing bacteria within.

Since the first discovery of unique carbon (C) and nitrogen (N) isotope signatures in fungal fruiting bodies (Gebauer & Dietrich, 1993; Gleixner et al., 1993), natural abundances of stable isotopes have been extensively used to identify the nutritional dynamics of fungi (Mayor et al., 2009). Assigning ecological roles of fungi is essential to determine the role of individual taxa in nutrient cycling and forest ecology. The use of isotope natural abundances in forest ecosystems has been crucial in distinguishing fungi with two main modes of life: ectomycorrhizal and saprotrophic fungi (Henn & Chapela, 2001). Within saprotrophic fungi, isotope natural abundances further allow the identification of the substrates used (Kohzu et al., 1999). Dual isotope analyses of the δ¹³C and δ¹⁵N values consistently indicate a differentiation in isotopic signatures between ectomycorrhizal and saprotrophic fungi within and among ecosystems (Henn & Chapela, 2001; Taylor et al., 2003; Trudell et al., 2004; Mayor et al., 2009). These signatures have been shown to reflect the ecophysiology of fungi and demonstrate that fungi that can utilize organic nitrogen exhibit higher δ¹⁵N than those fungi restricted to mineral nitrogen sources (Gebauer & Taylor, 1999; Lilleskov et al., 2002). Still, the ability to distinguish fungal nutritional modes has been long restricted to fungi that produce macroscopic sporocarps, such as mushrooms, due to their large mass which allows for physical measurements. Thus, for many fungi, particularly those associated with plant roots that do not form evident fruiting bodies, isotope natural abundances of fungal hyphae are scarce.

Besides ectomycorrhizal fungi, isotope natural abundances are known for sporocarp-forming ericoid (e.g. Hobbie & Hogberg, 2012) and orchid-associated nonrhizoctonia saprotrophic fungi (e.g. Ogura-Tsujita et al., 2009). Yet, values of δ¹³C and δ¹⁵N are poorly known for arbuscular mycorrhizal fungi (but see e.g. Courty et al., 2011; Suetsugu et al., 2020, for isotope values of fungal spores), and the orchid-associated fungi known as ‘rhizoctonia’ in natural conditions. Recently, Klink et al. (2020) obtained the δ¹³C and δ¹⁵N of arbuscular mycorrhizal hyphae isolated from roots of a grass and a legume, inoculated in experimental conditions, thereby providing an efficient method to extract hyphae from roots. Using this method with a few modifications, here, we measured the isotope natural abundances δ¹³C and δ¹⁵N of naturally occurring arbuscular mycorrhizal (Fig. 1a–c) and orchid-associated hyphae (Fig. 1d–f) directl

Corrigendum to New Phytologist 225 (2020), 1500–1515, doi: 10.1111/nph.16252.

Since its publication, the authors of Baudena et al. (2020) have identified an error for the set of parameter values representing flammability in Table 2. In this correction, the authors would also like to report that, when using the flammability values as originally published in Baudena et al. (2020; i.e. a factor 2 larger than those actually used in the simulations), the main results do not change qualitatively (see Supporting Information Figs S1, S2 to this correction).

Namely, when increased aridity was simulated as negatively affecting oak post-fire recovery and colonization rate, while positively affecting the community flammability, the authors observed that the forest state was resilient to the separate impact of fires and increased aridity. Yet, water stress could convert forests into open shrublands by hampering post-fire recovery and at the same time either increasing flammability or decreasing the oak forest colonization rate (or both). A tipping point (emerging from bistability of the open shrubland and forest state) was detected at intermediate levels of aridity (Fig. S1). In the ‘short-term’ run, that is a century, the authors observed again that the probability of a mixed successional community becoming an oak forest after 100 yr decreased drastically with increasing aridity (moving from bottom left to top right in Fig. S2, e.g. with flammability equal to 1.5 times the baseline value as published in table 2 in Baudena et al., 2020). The main differences between the two parameter sets were that the effects of aridity were more dramatic in Figs S1 and S2, as their baseline flammability (given in table 2 in Baudena et al., 2020) was twice as high as the baseline flammability that we actually used in figs 3 and 4 in Baudena et al. (2020) (as reported here in Table 2).

We apologize to our readers for this mistake.

The authors would like to kindly acknowledge Matilde Torrassa for finding the error in the original version of the paper.

Polyploidy, namely the acquisition of additional, complete sets of chromosomes to the genome, is widely recognized as a key feature of extant organismal diversity, particularly in plants. It is generally accepted that all angiosperm species have experienced at least one polyploidization event in their evolutionary past (Jiao et al., 2011). Therefore, most (if not all) plant species should be considered as paleo-polyploids that have since diploidized to some extent. As such, the distinction between diploids and polyploids should be made with respect to a reference timepoint. In recent decades, polyploid research has experienced a resurgence among plant evolutionary biologists. This is largely due to the use of genomic analyses that have revealed a rich history of genome duplications across multiple plant lineages. Indeed, numerous studies have investigated the impact of polyploidy on morphological and life-history traits, ecology, diversification patterns, and genome evolution (reviewed in Soltis & Soltis, 2000; Otto & Whitton, 2003; Ramsey & Schemske, 2003; Otto, 2007; Ramsey & Ramsey, 2014; Wendel, 2015; Soltis et al., 2016; Van de Peer et al., 2017; Fox et al., 2020). Notably, many of these studies focus on the effect of polyploidy in the context of a specific taxonomic group, which limits our ability to draw conclusions regarding the universal consequences of polyploidy, and to distinguish broad convergent trends from species-specific idiosyncrasies. There is thus a growing need to expand the examination of ploidy estimates across the seed plants clade, to obtain robust and broad information about the effect of polyploidy.

In the last few years, multiple methods for ploidy inferences based on sequenced genomic data have been developed (e.g. Jiao et al., 2011; Rabier et al., 2014; Vanneste et al., 2014; Tiley et al., 2018; Zwaenepoel & Van de Peer, 2020). However, due to the computational complexities and substantial amount of genomic data involved, the applications of such methods are still somewhat limited and are usually applied at phylogenetic scales above the species level, for example, by sampling representatives from several clades of interest. As such, the most comprehensive sequence-based analysis to date, which was conducted by the 1KP initiative and encompassed the transcriptomes of roughly 1100 plant species, has identified 244 whole-genome duplication (WGD) events occurring within Viridiplantae (One Thousand Plant Transcriptomes Initiative, 2019; Li & Barker, 2020).

Ploidy estimation at the species level is still largely based on information derived from chromosome numbers. A simple utility of chromosome number informatio

Plants have developed multilayered defense strategies to adapt and acclimate to the kaleidoscopic environmental changes that rapidly produce reactive oxygen species (ROS) and induce redox changes. Thiol-based redox sensors containing the redox-sensitive cysteine residues act as the central machinery in plant defense signaling. Here, we review recent research on thiol-based redox sensors in plants, which perceive the changes in intracellular H₂O₂ levels and activate specific downstream defense signaling. The review mainly focuses on the molecular mechanism of how the thiol sensors recognize internal/external stresses and respond to them by demonstrating several instances, such as cold-, drought-, salinity-, and pathogen-resistant signaling pathways. Also, we introduce another novel complex system of thiol-based redox sensors operating through the liquid–liquid phase separation.