Cold acclimation is a process used by most temperate plants to cope with freezing stress. In this process, the expression of cold-responsive ( COR ) genes is activated and the genes undergo physiological changes in response to the exposure to low, non-freezing temperatures and other environmental signals. The C-repeat-binding factors (CBFs) have been demonstrated to regulate the expression of many COR genes. Recent studies have elucidated the molecular mechanisms of how plants transmit cold signals from the plasma membrane to the CBFs and the results have indicated that COR genes are also regulated through CBF-independent pathways. Climate change is expected to have a major impact on cold acclimation and freezing tolerance of plants. However, how climate change affects plant cold acclimation at the molecular level remains unclear. This mini-review focuses on recent advances in cold acclimation in Arabidopsis thaliana and discusses how signaling can be potentially impacted by climate change. Understanding how plants acquire cold acclimation is valuable for the improvement of the freezing tolerance in plants and for predicting the effects of climate change on plant distribution and agricultural yield.

Reactive oxygen species (ROS) are constantly produced in plants, as the metabolic by-products or as the signaling components in stress responses. High levels of ROS are harmful to plants. In contrast, ROS play important roles in plant physiology, including abiotic and biotic tolerance, development, and cellular signaling. Therefore, ROS production needs to be tightly regulated to balance their function. Respiratory burst oxidase homologue (RBOH) proteins, also known as plant nicotinamide adenine dinucleotide phosphate oxidases, are well studied enzymatic ROS-generating systems in plants. The regulatory mechanisms of RBOH-dependent ROS production in stress responses have been intensively studied. This has greatly advanced our knowledge of the mechanisms that regulate plant ROS production. This review attempts to integrate the regulatory mechanisms of RBOHD-dependent ROS production by discussing the recent advance. AtRBOHD-dependent ROS production could provide a valuable reference for studying ROS production in plant stress responses.

Mitogen-activated protein kinase (MAPK) cascades are evolutionarily conserved modules among eukaryotic species that range from yeast, plants, flies to mammals. In eukaryotic cells, reactive oxygen species (ROS) has both physiological and toxic effects. Both MAPK cascades and ROS signaling are involved in plant response to various biotic and abiotic stresses. It has been observed that not only can ROS induce MAPK activation, but also that disturbing MAPK cascades can modulate ROS production and responses. This review will discuss the potential mechanisms by which ROS may activate and/or regulate MAPK cascades in plants. The role of MAPK cascades and ROS signaling in regulating gene expression, stomatal function, and programmed cell death (PCD) is also discussed. In addition, the relationship between Rboh-dependent ROS production and MAPK activation in PAMP-triggered immunity will be reviewed.

Populus, a core genus of Salicaceae, plays a significant ecological role as a source of pioneer species in boreal forests. However, interspecific hybridization and high levels of morphological variation among poplars have resulted in great difficulty in classifying species for systematic and comparative evolutionary studies. Here, we present phylogenetic analyses of 24 newly sequenced Populus plastomes and 36 plastomes from GenBank, which represent seven genera of Salicaceae, in combination with a matrix of eighteen morphological characters of 40 Populus taxa to reconstruct highly supported relationships of genus Populus. Relationships among the 60 taxa of Salicaceae strongly supported two monophyletic genera: Populus and Salix. Chosenia was nested within the genus Salix, and five clades within Populus were divided. Clade I included the three taxa P. euphratica, P. pruinosa, and P. ilicifolia. Clade II contained thirteen taxa [P. adenopoda, P. alba, P. bolleana, P. davidiana, P. hopeiensis, P. nigra, P. qiongdaoensis, P. rotundifolia, P. rotundifolia var. duclouxiana, P. tremula, P. tremula × alba, P. tomentosa, and P. tomentosa (NC)]. Clade III included the ten taxa P. haoana, P. kangdingensis, P. lasiocarpa, P. pseudoglauca, P. qamdoensis, P. schneideri, P. simonii, P. szechuanica, P. szechuanica var. tibetica, and P. yunnanensis. Clade IV included P. cathayana, P. gonggaensis, P. koreana, P. laurifolia, P. trinervis, P. wilsonii, and P. xiangchengensis. The last clade comprised P. angustifolia, P. balsamifera, P. deltoides, P. deltoides × nigra, P. fremontii, P. mexicana, and P. trichocarpa. This phylogeny is also supported by morphological traits, including bark smoothness, bud size, petiole shape, leaf inflorescence, male anther length and male anther tip.

Being a sister species of Saccharomyces cerevisiae, Saccharomyces uvarum shows great potential regarding the future of the wine industry. The sulfite tolerance of most S. uvarum strains is poor, however. This is a major flaw that limits its utility in the wine industry. In S. cerevisiae, FZF1 plays a positive role in the transcription of SSU1, which encodes a sulfite efflux transport protein that is critical for sulfite tolerance. Although FZF1 has previously been shown to play a role in sulfite tolerance in S. uvarum, there is little information about its action mechanism. To assess the function of FZF1, two over-expression vectors that contained different FZF1 genes, and one FZF1 silencing vector, were constructed and introduced into a sulfite-tolerant S. uvarum strain using electroporation. In addition, an FZF1-deletion strain was constructed. Both of the FZF1-over-expressing strains showed an elevated tolerance to sulfite, and the FZF1-deletion strain showed the opposite effect. Repression of FZF1 transcription failed, however, presumably due to the lack of alleles of DCR1 and AGO. The qRT-PCR analysis was used to examine changes in transcription in the strains. Surprisingly, neither over-expressing strain promoted SSU1 transcription, although MET4 and HAL4 transcripts significantly increased in both sulfite-tolerance increased strains. We conclude that FZF1 plays a different role in the sulfite tolerance of S. uvarum compared to its role in S. cerevisiae.