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Abstract Bacteria perceive light signals via photoreceptors and modulate many physiological and genetic processes. The impacts played by light, oxygen, or voltage (LOV) and blue light (BL) photosensory proteins on the virulence-related traits of plant bacterial pathogens are diverse and complex. In this study, we identified LOV protein (Pc-LOV1) from Pseudomonas cichorii JBC1 (PcJBC1) and characterized its function using LOV1-deficient mutant (JBC1Δlov1). In the dark state, the recombinant Pc-LOV1 protein showed an absorption band in UV-A region with a double peak at 340 nm and 365 nm, and within the blue-region, it exhibited a main absorption at 448 nm along with two shoulder peaks at 425 nm and 475 nm, which is a typical feature of oxidized flavin within LOV domain. The adduct-state lifetime (τrec) of Pc-LOV1 was 67.03 ± 4.34 min at 25 °C. BL negatively influenced the virulence of PcJBC1 and the virulence of JBC1Δlov1 increased irrespective of BL, indicating that Pc-LOV1 negatively regulates PcJBC1 virulence. Pc-LOV1 and BL positively regulated traits relevant to colonization on plant surface, such as adhesion to the plant tissue and biofilm formation. In contrast, swarming motility, exopolysaccharide production, and siderophore synthesis were negatively controlled. Gene expression supported the modulation of bacterial features by Pc-LOV1. Overall, our results suggest that the LOV photosensory system plays crucial roles in the adaptive responses and virulence of the bacterial pathogen PcJBC1. The roles of other photoreceptors, sensing of other wavelengths, and signal networking require further investigation.

Symbiotic microbes are essential for developing and growing Gastrodia elata, an achlorophyllous orchid of high medicinal value. Recently, the cultivation of G. elata in greenhouses has been adopted in Korea to produce mature tubers in a short time. However, no studies have been conducted on the microbial community structure of G. elata cultivated in greenhouse environments. Therefore, we analyzed the temporal features of bacterial and fungal communities in the rhizosphere of G. elata at the juvenile [JT; 2 months after sowing (MAS)], young (YT; 6 MAS), and mature (MT; 11 MAS) tuber stages using culture-dependent and high-throughput sequencing technology. The richness and diversity of the bacterial and fungal communities decreased with tuber growth of G. elata. The symbiotic fungi Mycena sp. and Armillaria sp. as well as tuber extract inhibited the growth of various soil-inhabiting fungal and bacterial strains, indicating that G. elata and its symbiotic fungi play important roles in the selection of rhizosphere microbes. Mortierella rishikesha was the most abundant fungal species in the rhizosphere. We also identified the microorganisms potentially beneficial for G. elata development during greenhouse cultivation. Tubers and symbiotic fungi actively exert selective pressure on rhizosphere microbes, influencing the diversity and abundance of bacterial and fungal communities as G. elata grows. This study is a first report on the temporal microbial community structure of G. elata cultivated in greenhouse. The results on the associated microbiome of G. elata will help understand their beneficial interactions with G. elata and contribute to improvement in cultivation.

Rapid economic growth and globalization have made higher education internationalization no longer the exclusive arena for developed countries but also open for players from the non-English speaking, developing world. A quality learning environment is among determinants for the success of international students mobility and should be taken into serious consideration by countries that want to prevail. However, much of the existing learning environment literature has targeted international students, ignoring the insights of other stakeholders, especially those from the host country side. This mixed-methods study investigated the perception and attitudes of EFL teachers and students towards the quality of the classroom learning environment (CLE) with the participation of international students in a university in Vietnam. Qualitative data from semi-structured interviews were used to interpret quantitative data collected via questionnaire surveys with 136 student participants. Findings showed a positive assessment of CLEs in the studied context. CLE factors such as student cohesiveness and task orientation were believed to be affected by the presence of international students, which could be attributed to communication barriers and challenges in organizing class activities. The findings contribute a robust understanding for further exploration of the under-researched realm of classroom environment with international students.

The wide use of English has given rise to the World Englishes (WE) paradigm, within which there has been a growing interest in the pedagogical implications of the varieties of English. A frequently documented rationale for the marriage between second language education and WE is that WE users should be aware of the potential problems in WE communication. This study adopts a qualitative case study, employing an Interpretative Phenomenological Approach (IPA) to explore the perception and experience of three Vietnamese university graduates of such WE communicative problems. The data collected through semi-structured interviews were analyzed through the lens of existing WE theories, especially the theory of intelligibility in communication. The findings confirm problems concerning sound recognition as the most frequent and dominant intelligibility issue while comprehensibility and interpretability problems vary and depend on the contexts of use. The data also yield information about the effects of WE problems on both the participants' feelings and their English proficiency. Findings from this study urge the integration of WE into current English as a Foreign Language (EFL) practice in Vietnam as a WE awareness can help build a critical understanding of languages and contribute to the formation of a positive identity of EFL/ English as a Second language (ESL) users.