Journal of Plant Research最新文献

Rice production is seriously affected by saline-alkaline stress worldwide. To elucidate the saline-alkaline tolerance mechanisms in a novel tolerant rice variety, Shwe Nang Gyi (SNG), we investigated ion accumulation in SNG and Koshihikari (KSH), which is a saline-alkaline sensitive rice variety, and the candidates for saline-alkaline inducible genes in SNG using RNA-seq. SNG had superior ion accumulation capacity, such as K and Zn, compared to KSH. In contrast, SNG accumulated the same level of Na content in its leaf blades as KSH despite the higher dry weight of the SNG leaf blades. We further found that the expression of numerous genes, including several K⁺ transporter/high-affinity K⁺ transporter/K⁺ uptake protein/K⁺ transporter (HAK/KUP/KT) family members, were upregulated in SNG, and that OsHAK17 and OsHAK21 expression levels in the roots were significantly higher in SNG than in KSH. Moreover, yeast complementation analysis revealed that OsHAK17 was involved in K⁺ uptake under high-Na conditions. These results suggested that SNG has an effective K⁺ acquisition system supported by OsHAK17 functioning in saline-alkaline environments.

The Chilean Puya species, Puya coerulea var. violacea and P. chilensis bear blue and pale-yellow flowers, respectively, while P. alpestris considered to be their hybrid-derived species has unique turquoise flowers. In this study, the chemical basis underlying the different coloration of the three Puya species was explored. We first isolated and identified three anthocyanins: delphinidin 3,3',5'-tri-O-glucoside, delphinidin 3,3'-di-O-glucoside and delphinidin 3-O-glucoside; seven flavonols: quercetin 3-O-rutinoside-3'-O-glucoside, quercetin 3,3'-di-O-glucoside, quercetin 3-O-rutinoside, isorhamnetin 3-O-rutinoside, myricetin 3,3',5'-tri-O-glucoside, myricetin 3,3'-di-O-glucoside and laricitrin 3,5'-di-O-glucoside; and six flavones: luteolin 4'-O-glucoside, apigenin 4'-O-glucoside, tricetin 4'-O-glucoside, tricetin 3',5'-di-O-glucoside, tricetin 3'-O-glucoside and selagin 5'-O-glucoside, which is a previously undescribed flavone, from their petals. We also compared compositions of floral flavonoid and their aglycone among these species, which suggested that the turquoise species P. alpestris has an essentially intermediate composition between the blue and pale-yellow species. The vacuolar pH was relatively higher in the turquoise (pH 6.2) and pale-yellow (pH 6.2) flower species, while that of blue flower species was usual (pH 5.2). The flower color was reconstructed in vitro using isolated anthocyanin, flavonol and flavone at neutral and acidic pH, and its color was analyzed by reflectance spectra and the visual modeling of their avian pollinators. The modeling demonstrated that the higher pH of the turquoise and pale-yellow species enhances the chromatic contrast and spectral purity. The precise regulation of flower color by flavonoid composition and vacuolar pH may be adapted to the visual perception of their avian pollinator vision.

The GARP (Golden2, ARR-B, Psr1) family proteins with a conserved DNA-binding domain, called the B-motif, are plant-specific transcription factors involved in the regulation of various physiological processes. The GARP family proteins are divided into members that function as monomeric transcription factors, and members that function as transcription factors in the dimeric form, owing to the presence of a coiled-coil dimerization domain. Recent studies revealed that the dimer-forming GARP family members, which are further divided into the PHR1 and NIGT1 subfamilies, play critical roles in the regulation of phosphorus (P) and nitrogen (N) acquisition. In this review, we present a general overview of the GARP family proteins and discuss how several members of the PHR1 and NIGT1 subfamilies are involved in the coordinated acquisition of P and N in response to changes in environmental nutrient conditions, while mainly focusing on the recent findings that enhance our knowledge of the roles of PHR1 and NIGT1 in phosphate starvation signaling and nitrate signaling.

Lemna aequinoctialis Welw. is a widely spread species that has diverse physiological and molecular properties. Flower characteristics are important factors in deducing taxonomical status; however, owing to the rarity of flowering observations in Lemna, studying them has been a prolonged challenge. In this study, physiological and morphological analyses were conducted by inducing flowering, and molecular analysis was done based on the two chloroplast DNA loci (matK, atpF-atpH intergeneric spacer) of L. aequinoctialis sensu Landolt (1986) from 70 strains found in 70 localities in Japan, Korea, Thailand, and the US. In total, 752 flowering fronds from 13 strains were observed based on axenic conditions. Two different trends in flower organ development-protogyny and adichogamy-were detected in these strains. Their physiological traits were divided into two groups, showing different morphological features based on frond thickness, root cap, and anther sizes. Molecular analysis showed two lineages corresponding to two physiological groups. These were identified as L. aequinoctialis sensu Beppu et al. (1985) and L. aoukikusa Beppu et Murata based on the description of the nomenclature of L. aoukikusa. These were concluded as independent taxa and can be treated as different species. Furthermore, the distribution of L. aoukikusa is not only limited to Japan.

The present review explains briefly the importance of phosphorus in the biological activities and states that the most phosphorus of living organisms is absorbed by plants from the soil. Next, previous studies on the mechanisms of phosphate uptake by plants are reviewed as H⁺-dependent or Na⁺-dependent co-transport systems and the phosphate environment in which plants grow is discussed. The evolution of transporter genes and their regulation mechanisms of expression is discussed in relation to the phosphorus environment.

Eomecon chionantha Hance, an endemic species in China, has a long medical history in Chinese ethnic minority medicine and is known for its anti-inflammatory and analgesic effects. However, studies of E. chionantha are lacking. In this study, we investigated the characteristics of the E. chionantha chloroplast genome and determined the taxonomic position of E. chionantha in Papaveraceae via phylogenetic analysis. In addition, we determined molecular markers to identify E. chionantha at the molecular level by comparing the chloroplast genomes of E. chionantha and its closely related species. The complete chloroplast genomic information indicated that E. chionantha chloroplast DNA (178,808 bp) contains 99 protein-coding genes, 8 rRNAs, and 37 tRNAs. Meanwhile, we were able to identify a total of 54 simple sequence repeats through our analysis. Our findings from the phylogenetic analysis suggest that E. chionantha shares a close relationship with four distinct species, namely Macleaya microcarpa, Coreanomecon hylomeconoides, Hylomecon japonica, and Chelidonium majus. Additionally, using the Kimura two-parameter model, we successfully identified five hypervariable regions (ycf4-cemA, ycf3-trnS-GGA, trnC-GCA-petN, rpl32-trnL-UAG, and psbI-trnS-UGA). To the best of our knowledge, this is the first report of the complete chloroplast genome of E. chionantha, providing a scientific reference for further understanding of E. chionantha from the perspective of the chloroplast genome and establishing a solid foundation for the future identification, taxonomic determination and evolutionary analysis of this species.

Ecophysiological studies of lichens in tropical Asia are rare, and additional studies can increase the understanding of lichen life in this region. The main aim of this study was to observe the relationships between water availability and photosynthetic parameters, as well as hydration trait parameters, in macrolichens during the rainy and dry seasons in a tropical forest. A total of 11 lichen species growing in a lower montane rainforest in Thailand were collected and studied. The results clearly showed that the specific thallus mass (STM), net photosynthetic rate (Pn), the potential quantum yield of primary photochemistry (Fv/Fm), chlorophyll content, and carotenoid content of almost all lichens were lower in the dry season than in the rainy season. Field measurements in the dry season revealed that only the foliose chlorolichen Parmotrema tinctorum was metabolically active and exhibited slight carbon assimilation. In the rainy season, all lichens started their photosynthesis in the early morning, reached maximal values, declined, and ceased when the thalli desiccated. The photosynthetically active period of the lichens was approximately 2–3 h in the morning, and the activities of the cyanolichens ended approximately 30 min after the chlorolichens. The hydration trait parameters, including the STM, maximal water content (WC_max), and water holding capacity (WHC), were greater in the cyanolichens. In addition, the maximal Pn (Pn_max) and optimal water content (WC_opt) for Pn were also greater in the cyanolichens, but the maximal Fv/Fm (Fv/Fm_max) was lower. The cyanolichens compensated for their inability to use humid air to restore photosynthesis by having higher water content and storage, higher photosynthetic rates, and longer photosynthetically active periods. This study provides additional insights into lichen ecophysiology in tropical forests that can be useful for lichen conservation.

Chloroplast-actin (cp-actin) filaments are crucial for light-induced chloroplast movement, and appear in the front region of moving chloroplasts when visualized using GFP-mouse Talin. They are short and thick, exist between a chloroplast and the plasma membrane, and move actively and rapidly compared to cytoplasmic long actin filaments that run through a cell. The average period during which a cp-actin filament was observed at the same position was less than 0.5 s. The average lengths of the cp-actin filaments calculated from those at the front region of the moving chloroplast and those around the chloroplast periphery after stopping the movement were almost the same, approximately 0.8 µm. Each cp-actin filament is shown as a dotted line consisting of 4–5 dots. The vector sum of cp-actin filaments in a moving chloroplast is parallel to the moving direction of the chloroplast, suggesting that the direction of chloroplast movement is regulated by the vector sum of cp-actin filaments. However, once the chloroplasts stopped moving, the vector sum of the cp-actin filaments around the chloroplast periphery was close to zero, indicating that the direction of movement was undecided. To determine the precise structure of cp-actin filaments under electron microscopy, Arabidopsis leaves and fern Adiantum capillus-veneris gametophytes were frozen using a high-pressure freezer, and observed under electron microscopy. However, no bundled microfilaments were found, suggesting that the cp-actin filaments were unstable even under high-pressure freezing.

Leaf form can vary at different levels, such as inter/intraspecies, and diverse leaf shapes reflect their remarkable ability to adapt to various environmental conditions. Over the past two decades, considerable progress has been made in unraveling the molecular mechanisms underlying leaf form diversity, particularly the regulatory mechanisms of leaf complexity. However, the mechanisms identified thus far are only part of the entire process, and numerous questions remain unanswered. This review aims to provide an overview of the current understanding of the molecular mechanisms driving leaf form diversity while highlighting the existing gaps in our knowledge. By focusing on the unanswered questions, this review aims to shed light on areas that require further research, ultimately fostering a more comprehensive understanding of leaf form diversity.

The nurse effect is a positive interaction in which a nurse plant improves the abiotic environment for another species (beneficiary plant) and facilitates its establishment. The evergreen shrub Vaccinium vitis-idaea (a beneficiary plant) grows mainly under the dwarf shrub Pinus pumila (a nurse plant) in the alpine regions of central Japan. However, whether V. vitis-idaea shrubs under various P. pumila shrubs spread through clonal growth and/or seeds remains unclear. We investigated the clonal structure of V. vitis-idaea under the nurse plant P. pumila in Japanese alpine regions. MIG-seq analysis was conducted to clarify the clonal diversity of V. vitis-idaea in isolated and patchy P. pumila plots on a ridge (PATs), and in a plot covered by dense P. pumila on a slope adjacent to the ridge (MAT) on Mt. Norikura, Japan. We detected 28 multilocus genotypes in 319 ramets of V. vitis-idaea across 11 PATs and MAT. Three genets expanded to more than 10 m in the MAT. Some genets were shared among neighboring PATs or among PATs and MAT. These findings suggest that the clonal growth of V. vitis-idaea plays an important role in the sustainability of populations. The clonal diversity of V. vitis-idaea was positively related with the spatial size of PATs and was higher in MAT than in PATs at a small scale. Therefore, the spatial spread of the nurse plant P. pumila might facilitate the nurse effect on the genetic diversity of beneficiary plants, leading to the sustainability of beneficiary populations.