Transpiration occurs through stomata. The alteration of stomatal apertures in response to drought stress is an important process associated with water use efficiency (WUE). Trehalose-6-phosphate phosphatase (TPP) family genes have been reported to participate in stomatal aperture adjustment. However, there have been no reports of the trehalose metabolism pathway genes improving WUE, and the upstream signalling pathway modulating these genes is not clear. Here, we demonstrated that a member of the TPP gene family, AtTPPI, confers drought resistance and improves WUE by decreasing stomatal apertures and improving root architecture. The reduced expression of AtTPPI caused a drought-sensitive phenotype, while its overexpression significantly increased drought tolerance. Abscisic acid (ABA)-induced stomatal closure experiments confirmed that AtTPPI mutation increased the stomatal aperture compared to that of wild-type (WT) plants; in contrast, overexpression plants had smaller stomatal apertures than those of WT plants. Moreover, AtTPPI mutation also caused stunted primary root length and compromised auxin transport, while overexpression plants had longer primary root lengths. Yeast one-hybrid assays showed that ABA-responsive element-binding factor1 (ABF1), ABF2 and ABF4 directly regulated AtTPPI expression. In summary, the way AtTPPI responds to drought stress suggests that AtTPPI-mediated stomatal regulation is an important mechanism to cope with drought stress and improve WUE.

Simple and consistent production of haploid is always an appealing pursuit for both crop breeders and researchers. Although diverse strategies have been developed to produce haploids over the past decades, most of them are applicable in only a limited number of plant species. In 2010, Ravi and Chan reported that haploid Arabidopsis thaliana plants can be efficiently induced through the introduction of a single genetic alteration in centromere histone H3 (CENH3). Subsequent studies demonstrated that haploids can be efficiently induced either through genetic engineering of CENH3 N-terminal tail or histone fold domain or by replacing CENH3 with an ortholog. The mutation of a pollen-specific phospholipase gene, MATRILINEAL (MTL) has been revealed to trigger the haploid induction (HI) in maize, which present another promising HI approach by the editing of MTL in plant. Here, we review the progress of the CENH3-medialed HI and propose a revised centromere-size model by suggesting a competitive loading process between wild-type and mutant CENH3 during HI. This model can explain both the findings of HI failure when wild-type and mutant CENH3 genes are coexpressed and the alien centromere loading of CENH3 in stable hybrids. In addition, we review the current understanding of MTL-mediated HI in plant. The conservation of CENH3 and MTL in plants indicates wide potential application for HI. We discuss the utility and potential of these two methods in crops by comparing their mechanisms and applications to date in plants. This review will promote the study and application of both CENH3- and MTL-mediated haploid induction in plants.

Trehalose biosynthesis enzyme homologues in plants contain two families, trehalose-6-phosphate synthases (TPSs) and trehalose-6-phosphate phosphatases (TPPs). Both families participate in trehalose synthesis and a variety of stress-resistance processes. Here, nine BdTPS and ten BdTPP genes were identified based on the Brachypodium distachyon genome, and all genes were classified into three classes. The Class I and Class II members differed substantially in gene structures, conserved motifs, and protein sequence identities, implying varied gene functions. Gene duplication analysis showed that one BdTPS gene pair and four BdTPP gene pairs are formed by duplication events. The value of Ka/Ks (non-synonymous/synonymous) was less than 1, suggesting purifying selection in these gene families. The cis-elements and gene interaction network prediction showed that many family members may be involved in stress responses. The quantitative real-time reverse transcription (qRT-PCR) results further supported that most BdTPSs responded to at least one stress or abscisic acid (ABA) treatment, whereas over half of BdTPPs were downregulated after stress treatment, implying that BdTPSs play a more important role in stress responses than BdTPPs. This work provides a foundation for the genome-wide identification of the B. distachyon TPS–TPP gene families and a frame for further studies of these gene families in abiotic stress responses.

Autophagy is a highly conserved self-degradation mechanism in eukaryotes. Excess or harmful intracellular content can be encapsulated by double-membrane autophagic vacuoles and transferred to vacuoles for degradation in plants. Current research shows three types of autophagy in plants, with macroautophagy being the most important autophagic degradation pathway. Until now, more than 40 autophagy-related (ATG) proteins have been identified in plants that are involved in macroautophagy, and these proteins play an important role in plant growth regulation and stress responses. In this review, we mainly introduce the research progress of autophagy in plant vegetative growth (roots and leaves), reproductive growth (pollen), and resistance to biotic (viruses, bacteria, and fungi) and abiotic stresses (nutrients, drought, salt, cold, and heat stress), and we discuss the application direction of plant autophagy in the future.

Bacterial leaf streak (BLS) is a destructive bacterial disease in rice. To date, at least 13 quantitative trait loci (QTLs) conferring resistance to BLS have been identified in rice, while only one QTL, qBlsr5a, has been fine mapped and cloned. The present study focuses on fine mapping of qBlsr3d, a minor QTL conferring resistance to BLS. To fine map this QTL, 24 overlapping chromosome segment substitution lines (CSSLs) were developed from the F₂ population derived from H359 × H359‐BLSR3D. Combining genotyping of molecular markers with resistance performance, qBlsr3d was delimited to an 81‐kb interval on chromosome 3, which included 12 annotated genes. Sequence alignment indicated that one of the 12 candidate genes, LOC_Os03g03570, has 3 nucleotide substitutions (positions 1039, 2101 and 2113) in the CDS region between H359 and H359‐BLSR3D. In particular, LOC_Os03g03570 encodes a leucine‐rich repeat transmembrane protein, which has been reported to be associated with disease resistance, suggesting that LOC_Os03g03570 may be the target gene. Our research suggests that CSSLs are suitable for the mapping of minor QTLs related to disease resistance. Furthermore, our findings can be exploited to breed rice varieties that are resistant to BLS in the future. This article is protected by copyright. All rights reserved