DNA binding with one finger (Dof) proteins, forming an important transcriptional factor family, are involved in gene transcriptional regulation, development, stress responses, and flowering responses in annual plants. However, knowledge of Dofs in perennial and erratically flowering moso bamboo is limited. In view of this, a Dof gene, PheDof12-1, was isolated from moso bamboo. PheDof12-1 is located in the nucleus and has the highest expression in palea and the lowest in bract. Moreover, PheDof12-1 expression is high in flowering leaves, then declines during flower development. The transcription level of PheDof12-1 is highly induced by cold, drought, salt, and gibberellin A3 (GA₃) stresses. The functional characteristics of PheDof are researched for the first time in Arabidopsis, and the results show that transgenic Arabidopsis overexpressing PheDof12-1 shows early flowering under long-day (LD) conditions but there is no effect on flowering time under short-day (SD) conditions; the transcription levels of FT, SOC1, and AGL24 are upregulated; and FLC and SVP are downregulated. PheDof12-1 exhibits a strong diurnal rhythm, inhibited by light treatment and induced in dark. Yeast one-hybrid (Y1H) assay shows that PheDof12-1 can bind to the promoter sequence of PheCOL4. Taken together, these results indicate that PheDof12-1 might be involved in abiotic stress and flowering time, which makes it an important candidate gene for studying the molecular regulation mechanisms of moso bamboo flowering.

Roots are essential for plant growth and development. Bamboo is a large Poaceae perennial with 1642 species worldwide. However, little is known about the transcriptional atlas that underpins root cell-type differentiation. Here, we set up a modified protocol for protoplast preparation and report single-cell transcriptomes of 14 279 filtered single cells derived from the basal root tips of moso bamboo. We identified four cell types and defined new cell-type-specific marker genes for the basal root. We reconstructed the developmental trajectories of the root cap, epidermis, and ground tissues and elucidated critical factors regulating cell fate determination. According to in situ hybridization and pseudotime trajectory analysis, the root cap and epidermis originated from a common initial cell lineage, revealing the particularity of bamboo basal root development. We further identified key regulatory factors for the differentiation of these cells and indicated divergent root developmental pathways between moso bamboo and rice. Additionally, PheWOX13a and PheWOX13b ectopically expressed in Arabidopsis inhibited primary root and lateral root growth and regulated the growth and development of the root cap, which was different from WOX13 orthologs in Arabidopsis. Taken together, our results offer an important resource for investigating the mechanism of root cell differentiation and root system architecture in perennial woody species of Bambusoideae.

Microalgae are promising microorganisms used to produce value-added products or to develop sustainable approaches for environmental remediation. The ATP-binding cassette proteins (ABCs) of Chlamydomonas reinhardtii have been characterized as indispensable transporters for CO₂ concentrating mechanism, lipid biosynthesis, and heavy metal sequestration. However, few microalgal ABC proteins have been studied compared with higher plants or non-photosynthetic microorganisms. This study performed a genome-wide, evolutionary, and transcriptomic survey of C. reinhardtii ABC proteins (CrABCs). A total of 75 CrABCs were identified and classed into eight ABC subfamilies, from ABCA to ABCI. We found that no whole or partial genome duplication events occurred in C. reinhardtii after the ancient endosymbiosis events, but gene duplications occurred in a small range of chromosomal regions, which forced ABC family expansion. Abundant light, abscisic acid, and jasmonic acid response cis-elements were mapped in the CrABC promoters, coinciding with the evolutionary history of hormone signaling in Chlorophyta. The expression survey under light/dark rhythms revealed a close bond of CrABCs with cell division and development. A broad study of CrABCs supported their expected roles in heavy metal detoxification, lipid metabolism, and environmental adaptation. Moreover, the evolutionary and expression survey predicted the functions of unknown CrABCs, which are elaborated in the text. Two half-size CrABCGs—CrABCG3 and CrABCG26—were described as plasma-membrane transporters that might participate in lipidic compound secretion. This study provides fundamental and exhaustive information about CrABCs, which are indispensable for the functional elucidation of ABC proteins in microalgae.

Heat shock transcription factors (Hsfs) play crucial roles in regulating plant responses to heat and other stresses, as well as in plant development. As the largest monopodial bamboo species in the world, how to adapt to various stresses under the background of global climate change is very important for the sustainable development of bamboo forest. However, our understanding of the function of Hsfs in moso bamboo (Phyllostachys edulis) is limited. In this study, a total of 22 non-redundant Hsf genes were identified in the moso bamboo genome. Structural characteristics and phylogenetic analysis revealed that members of the PheHsf family can be clustered into three classes (A, B and C). Furthermore, PheHsfs promoters contained a number of stress-, hormone- and development-related cis-acting elements. Transcriptome analysis indicated that most PheHsfs participate in rapid shoot growth and flower development in moso bamboo. Moreover, the expression patterns of all 12 members of class A were analyzed under various stresses (heat, drought, salt and cold treatment) through Figurereal-time quantitative polymerase chain reaction (qRT-PCR). Within the class A PheHsf members, PheHsfA1a was expressed mainly during moso bamboo development. Expression of four PheHsfA4s and one PheHsfA2 (PheHsfA4a-1, PheHsfA4a-2, PheHsfA4d-1, PheHsfA4d-2, and PheHsfA2a-2) was up-regulated in response to various stresses. PheHsfA2a-2, PheHsfA4d-1 and PheHsfA4d-2 were strongly induced respectively by heat, drought and NaCl stress. Through co-expression analysis we found that two hub genes PheHsfA4a-2 and PheHsfA4a-1 were involved in a complex protein interaction network. Based on the prediction of protein interaction networks, five PheHsfAs (PheHsfA4a-1, PheHsfA4a-2, PheHsfA4d-1, PheHsfA4d-2, and PheHsfA2a-2) were predicted to play an important role in flower and shoot development and abiotic stress response of moso bamboo. This study provides an overview of the complexity of the PheHsf gene family and a basis for analyzing the functions of PheHsf genes of interest.

Host defense peptides (HDPs) are components of plant defensive barriers that resist microbial infection. Members of the Snakin/GASA protein family in plants have functions of regulating plant growth, defense, and bacteriostasis. Most mangrove plants grow in coastal zones. In order to survive in harsh environments, mangrove plants have evolved complex adaptations against microbes. In this study, Snakin/GASA family members were identified and analyzed in the genomes of three mangrove species. Twenty-seven, thirteen, and nine candidate Snakin/GASA family members were found in Avicennia marina, Kandelia obovata, and Aegiceras corniculatum, respectively. These Snakin/GASA family members were identified and categorized into three subfamilies via phylogenetic analysis. The genes coding for the Snakin/GASA family members were unevenly distributed on chromosomes. Collinearity and conservative motif analyses showed that the Snakin/GASA family members in K. obovata and A. corniculatum underwent multiple gene duplication events. Snakin/GASA family member expression in normal leaves and leaves infected with pathogenic microorganisms of the three mangrove species was verified using real-time quantitative polymerase chain reaction. The expression of KoGASA3 and 4, AcGASA5 and 10, and AmGASA1, 4, 5, 15, 18, and 23 increased after microbial infection. This study provides a research basis for the verification of HDPs from mangrove plants and suggests directions for the development and utilization of marine biological antimicrobial peptides.