Plant Elongation Research Articles

Collaboration between DELLA and MED15 to regulate transcription in plants.

Gibberellins (GA) are diterpenoids that are categorized as one of main hormones that promote major developmental responses such as germination and stem elongation in plants. DELLA proteins act as the key repressors of GA responses. They interact with hundreds of different proteins. While the functioning of DELLA as transcriptional coactivators has also been reported earlier, the actual mechanism still remains elusive. One recent report describes interaction of DELLA with Mediator subunit MED15 as one of the mechanisms contributing to its transcription activation capability (Hernández-García et al. 2024). Interestingly, this mechanism of DELLA-MED15 module-mediated transcription regulation seems to be very ancient conserved from bryophyte Marchantia polymorpha to dicot Arabidopsis thaliana.

SlCIPK9 regulates pollen tube elongation in tomato plants via a K+-independent mechanism

Potassium (K+) is an essential macronutrient which contributes to osmotic- and turgor-related processes in plants. Calcineurin-B like Interacting Protein Kinases (CIPKs) play crucial roles in plants under low-K+ supply since they activate root K+ uptake transport systems such as AKT1 and AtHAK5. In Arabidopsis, AtCIPK9 is important for low-K+ tolerance since atcipk9 plants exhibited poor growth and leaf chlorosis when K+ was scarce. Part of these phenotypes could be ascribed to the activation of AtHAK5 by AtCIPK9. It has been reported that important differences exist between Arabidopsis and other plant species such as tomato with respect to the regulation of K+ uptake systems. Thus, our aim was to evaluate the contribution of SlCIPK9, the homologous protein of AtCIPK9 in tomato, to K+ nutrition. Unexpectedly, phenotyping experiments carried out with slcipk9 loss-of-function mutants revealed that SlCIPK9 did not play a clear role in tomato K+ homeostasis. By contrast, it was found that SlCIPK9 contributed to pollen tube elongation, but not to pollen germination, via a K+-independent mechanism. Therefore, our results highlight the remarkable differences that exist in Ca2+ signaling pathways between plant species and encourage the realization of more comparative studies as the one presented here.

An ABC transporter-mediated transport and metabolism of the pesticide bentazone in rice (Oryza sativa L.)

IntroductionBentazon (BNTZ) is a selective contact herbicide widely used to control field weeds for crop production. Excessive use of BNTZ leads to its accumulation in soils and crops, becoming an environmental contaminant. Therefore, investigation of the mechanisms for BNTZ detoxification and degradation in crops is fundamentally important to reduce crop contamination and ensure food safety. ObjectivesThis study aims to elucidate the mechanism of detoxification and degradation pathways of the BNTZ complex in rice by creating transgenic lines expressing a rice ATP-binding cassette (OsABC) transporter gene through genetic engineering techniques combined with chemical analytical techniques and metabolomics approaches. MethodsWe established the rice transgenic lines overexpressing (OE) a rice OsABC transporter and its knockout lines by CRISPR-Cas9 to characterize the gene function and measured the accumulation of BNTZ residues in rice. The metabolites of BNTZ were characterized by LC/Q-TOF-HRMS/MS (Liquid chromatography/time of flight-high resolution mass spectrometry). ResultsOverexpression of OsABC significantly conferred rice resistance to BNTZ toxicity by increasing plant elongation, dry weight, and chlorophyll content, and significantly reducing cell membrane damage and BNTZ accumulation in rice tissues. Six different metabolites and ten conjugates were well defined in chemical structures. The reduced BNTZ levels and degradation products in the grains of the OE lines supported the robust activity of the OsABC gene function.Using UPLC-Q-TOF/MS, we further identified accumulated basic metabolites of various carbohydrates, amino acids, hormones, and flavonoids, and found that these metabolites involved in BNTZ degradation were increased more in OE lines than in wild-type (WT) rice. ConclusionsOur work demonstrates that the OsABC transporter plays a critical role in regulating the mobility and degradative metabolism of BNTZ in rice, thus revealing a regulatory mechanism underlying rice resistance to BNTZ toxicity and adaptation to the environmental stress.

Endogenous cytokinins in plants of Secale cereale (Poaceae) under the effects of soil drought

Due to ongoing global climate changes and anthropogenic stress, soil drought has emerged as a significant threat, hindering plant growth, development, and resulting in crop losses. While phytohormones play a vital role in the formation of stress resistance mechanisms, cytokinins, in particular, remain poorly understood in cultivated cereals. The objective of our study was to investigate the impact of soil drought on plant growth and the homeostasis of endogenous cytokinins in both the aerial parts and roots of winter rye (Secale cereale) during the initial stages of vegetation. We aimed to elucidate the relationship between growth processes and the balance of these phytohormones. The plants were cultivated in a phytochamber using sand culture, and drought stress was induced by withholding water from nine-day-old plants for a period of eight days. The shoots and roots of 17-day-old plants were collected when dehydrated plants reached the critical wilting point. The content of endogenous cytokinins was analyzed using HPLC-MS. Our findings revealed that the inhibition of shoot growth and root elongation in stressed plants coincided with a reduction in the content of trans-zeatin riboside. This observation suggests that trans-zeatin riboside acts as a growth regulator in winter rye under soil drought conditions. Moreover, we observed an elevation in the levels of trans-zeatin and isopentenyladenine in the shoots and roots of stressed rye plants, indicating the involvement of these hormones in the formation of a "protective anti-stress block." These results highlight the multifunctional activity of cytokinins and demonstrate their role in regulating various components of the water deficit response. Consequently, our study expands our understanding of the role of cytokinins in the development of stress resistance in cereals.

Genetic Map Construction and Primary Quantitative Trait Locus Analysis of Low-Light-Stress-Related Traits in Cucumber

To ascertain the effect of low-light stress (80 μmol·m−2·s−1) on cucumbers, we report on improving and breeding low-light-tolerant varieties by mining genes related to low-light tolerance. In this study, the quantitative trait locus (QTL) mapping of cucumber plant height and internode length under low-light stress was conducted using the F2 population, employing specific-length amplified fragment sequencing (SLAF-seq) and phenotypic analysis. A genetic map with a total length of 1114.29 c M was constructed from 1,076,599 SNPs, and 2233 single-nucleotide polymorphism (SNP) markers were distributed on seven linked groups, with an average map distance of 0.50 c M. Two QTLs related to plant height, CsPlH5.1 and CsPlH6.1, were detected on Chr.5 and Chr.6, with a cumulative contribution rate of 16.33%. The contribution rate (PVE), max LOD value, additive effect (ADD), and dominant effect (DOM) of CsPlH5.1 were 9.446%, 4.013, 1.005, and 0.563, respectively. CsPlH5.1 was located between 4,812,907 and 5,159,042 in the Gy14_V2.0 genome of cucumber, with a genetic distance of 0.32 Mb; the interval contained 41 candidate genes, and CsPlH6.1 was found to be located between Marker537985 (171.10 c M) and Marker537984 (171.55 c M), a range containing only one candidate gene. A total of 42 candidate genes related to photosynthesis, chloroplast development, abiotic stress, and plant growth were found in the location range associated with plant height. Simultaneously, a QTL (Csnd2_NdL6.1) for the second internode length was detected, and the max LOD, ADD, and DOM values were 5.689, 0.384, and −0.19, respectively. Csnd2_NdL6.1 was located between 29,572,188 and 29,604,215, with 0.03 Mb on Chr.6 including seven candidate genes. The molecular function of the CsGy6G032300 gene is involved with the binding of calcium ions, which may be related to the elongation and growth of plants; however, the population needs to be further expanded for acceptable localization verification. The results of this study provide a preliminary basis for the mining of essential genes of cucumber’s low-light tolerance and identifying low-light-tolerance genes.

Origami-inspired highly stretchable and breathable 3D wearable sensors for in-situ and online monitoring of plant growth and microclimate

The emerging wearable plant sensors demonstrate the capability of in-situ measurement of physiological and micro-environmental information of plants. However, the stretchability and breathability of current wearable plant sensors are restricted mainly due to their 2D planar structures, which interfere with plant growth and development. Here, origami-inspired 3D wearable sensors have been developed for plant growth and microclimate monitoring. Unlike 2D counterparts, the 3D sensors demonstrate theoretically infinitely high stretchability and breathability derived from the structure rather than the material. They are adjusted to 100% and 111.55 mg cm−2·h−1 in the optimized design. In addition to stretchability and breathability, the structural parameters are also used to control the strain distribution of the 3D sensors to enhance sensitivity and minimize interference. After integrating with corresponding sensing materials, electrodes, data acquisition and transmission circuits, and a mobile App, a miniaturized sensing system is produced with the capability of in-situ and online monitoring of plant elongation and microclimate. As a demonstration, the 3D sensors are worn on pumpkin leaves, which can accurately monitor the leaf elongation and microclimate with negligible hindrance to plant growth. Finally, the effects of the microclimate on the plant growth is resolved by analyzing the monitored data. This study would significantly promote the development of wearable plant sensors and their applications in the fields of plant phenomics, plant-environment interface, and smart agriculture.

Reguladores de crescimento influenciam a altura e a partição de biomassa de plantas de mamona

ABSTRACT Castor (Ricinus communis) is a drought-resistant oilseed crop. This study evaluated five plant growth regulators (PGR) on their capacity to influence stem elongation of castor plants growing under shade and measured side effects on the biomass allocation among leaf, stem, and roots. The experiment had 220 castor plants of the cultivar AKB 02, on a completely randomized design and four replicates. The plants were kept under artificial shade and treated with 11 doses of PGR, applied in the first day after emergence. Eight plants were exposed to full sun radiation without PGR treatment. The plant height was measured daily, and the plants were harvested for weighing the final biomass. The data was subjected to multiple linear regression. The shade promoted stem elongation and reduced biomass accumulation in all compartments. The height growth was restricted by trinexapac-ethyl, mepiquat chloride, and chlormequat chloride. Gibberellin promoted stem elongation in addition to the shade effect. Paclobutrazol did not influence stem elongation, but it favored biomass accumulation and increased the stem density. Gibberellin promoted allocation to stem replacing leaf biomass; trinexapac-ethyl promoted root replacing stem and leaf biomass; mepiquat and chlormequat chloride promoted stem in detriment of leaf biomass. In conclusion, plant growth regulators may be effective to restrict height growth of castor plants, but they can also disturb the biomass allocation among root, stem, and leaves.

High sensitivity of hop plants (Humulus lupulus L.) to limited soil water availability: the role of stomata regulation and xylem vulnerability to embolism

Drought poses a serious threat to the productivity of hop, an important perennial crop. However, the precise physiological mechanisms that make it highly susceptible to drought are not yet fully understood. In this study, we investigated stomatal regulation and xylem vulnerability to embolism, which are important traits closely associated with plant drought resistance. In a glasshouse cultivation experiment, we monitored changes in leaf water potential, stem elongation rates, and leaf gas exchange, including net photosynthetic rates, stomatal conductance, and intrinsic water use efficiency, on relatively young hop plants (traditional Saaz - Osvald’s clone 31) exposed to declining soil water availability. The transpiration rate and stem elongation of plants decreased significantly with a small decline in substrate water potential (ΨSUB), indicating a highly sensitive stomata response during early phases of soil dehydration. The stem elongation was completely halted, and the transpiration rate dropped to less than 50% of its maximum at ΨSUB levels below − 0.8 MPa. In well-watered hop plants, xylem in stems operates near the initial point of embolization and is highly vulnerable to embolism, with a water potential corresponding to a 50% loss of xylem conductivity at -1.6 MPa. The sensitive stomatal response to declining ΨSUB likely helps to mitigate the risk of hydraulic failure, albeit at the cost of impaired growth. Scheduled irrigation, particularly during the sensitive stem elongation stage, may be a promising approach to mitigate the detrimental effects of reduced soil water availability on hop growth and yield while also conserving water resources.

Morphogenic characteristics of black oat and vetch under different densities

The objective of this study was to assess the morphogenic characteristics Avena strigosa and Vicia sativa plants cultivated in different sowing densities. The experiment was conducted in vases with farming soil. The experimental design involved randomized units, with four repetitions, consisting of a single vetch plant placed in the centre of each experimental unit and a variable number of oat plants (0, 1, 2, 3, 4, and 5) planted around the borders. The same procedure was also conducted with a single oat plant placed in the centre of the vase and a variable number of vetch plants (0, 1, 2, 3, 4, and 5) planted around the borders. The plants were grown for a total of 35 days. Morphogenic characteristics of the central plant were assessed at the time of transplantation as well as every 7 days. It was observed that the density increase in vetch plants did not significantly influence stem elongation, plant elongation, and leaf senescence rates of oat plants. However, higher densities did reduce the tiller appearance rate in oat plants. Increases in oat density caused significant impacts on the elongation rate and linear growth in the leaf senescence rate and reduced the number of ramifications in vetch plants. Higher density caused reduced leaf appearance and tiller rates while increasing phyllochron values. The results of this study indicate that increases in plant density trigger competition responses in both oat and vetch, which in turn negatively affect many of the assessed morphogenic characteristics for both species.

The Short Inflorescence Mutation in Diploid Strawberry Fragaria vesca Affects Inflorescence Architecture and Runner Elongation

Mutants are useful for determining the genes that underlie a given trait. This information is highly useful for developing molecular markers for breeding and is the foundational knowledge required for future genomic crop improvements. The dessert strawberry, Fragaria ×ananassa, is a valuable crop with high potential for increased use in controlled environment agriculture. The genome of the woodland strawberry Fragaria vesca is the dominant genome of the four diploid strawberry subgenomes that contribute to the octoploid F. ×ananassa genome. F. vesca is therefore a useful reference system for determining gene function and should be a useful source of gene diversity for breeding of F. ×ananassa. Chemical mutagenesis of the inbred F. vesca line H4 F7-3 resulted in one M2 line with a smaller stature overall and which produces flowers on very short peduncles close to the crown. This line was named short inflorescence (sin). The sin phenotype results from a single gene recessive mutation that is pleiotropic in that the mutation also affects internode lengths of runners as well as petiole elongation of sin plants. Microscopic characterization revealed that sin peduncles are most likely short because of a failure of cells to elongate. Inflorescences, runners, and petioles of sin plants were found to elongate in response to exogenous gibberellin, indicating that sin could be a gibberellin biosynthesis or transport mutant. A brief characterization of sin plants is presented to facilitate collaborative studies of the line.

Formation of biometric parameters of sowings of soybean variety ‘Sirelia’ on typical chernozems depending on the nutrition area

Purpose. To determine the effect of row width and seeding rate on the biometric parameters of sowings of the early-ripening soybean variety 'Sirelia'. Methods. The research was carried out in 2021–2023 in the stationary crop rotation of the Plant Breeding Department in the fields of the Agronomic Research Station of the National University of Life and Environmental Sciences of Ukraine (Pshenychne, Vasylkiv district, Kyiv region). Scheme of the experiment: factor A – sowing method: ordinary row with a row spacing of 19 cm; strip with a row spacing of 19 × 38 × 12 cm; wide-row with a row spacing of 38 cm; factor B – seeding rate: 450, 600 and 750 thousand seeds/ha. Recordings were carried out in the main phases of crop development: budding, flowering and grain filling. Results. The thickening of crops with an increase in the seeding rate from 450 to 750 thousand seeds/ha contributed to a significant increase in the height of soybean plants: by 3.5 cm for row spacings of 19 cm and by 5.9 cm for row spacing of 38 cm. Seeding rate of 450,000 seeds/ha led to a decrease in plant height by 4.1 cm, or 5.2%. Thus, from the given data it can be concluded that the height of soybean plants increased with an increase in the seeding rate. The influence of the sowing rate on the growth of plants at a row width of 38 cm was particularly significant. The absolute dry mass of plants in the budding phase was within the range of 2.87–4.00 g, in the flowering stage 4.81–6.93 g, and in the seed filling stage 11.6–21.5 g. During the last period, the mass of plants in the case of increasing the seeding rate from 450 to 750 thousand seeds/ha decreased by 8.9 g, for a row spacing of 19 cm, and for a row spacing 38 cm by 7.3 g. The highest mass of plants was for the row width of 38 cm and the sowing rate of 450,000 seeds/ha. Conclusions. The height of soybean plants increases with an increase in the seeding rate. This is explained by the fact that the thickening of crops causes shading and elongation of plants. Soybean plants were the highest (81.9 cm) at a row spacing of 38 cm and a seeding rate of 750,000 seeds/ha. The highest absolute dry weight of one soybean plant was formed at a seeding rate of 450,000 seeds/ha, and significantly decreases in case of its increase to 750 thousand seeds/ha for all methods of sowing. That is, the thickening of crops with an increase in the seeding rate from 450 to 750 thousand units/ha led to a significant decrease in the dry weight of plants, which is explained by the deterioration of the conditions for their growth and development, primarily due to high competition for life factors.

A Characterization of the Functions of OsCSN1 in the Control of Sheath Elongation and Height in Rice Plants under Red Light

The COP9 signalosome (CSN) is a conserved protein complex, with CSN1 being one of the largest and most important subunits in the COP9 complex. To investigate the N-terminus function of OsCSN1, we edited the N-terminus of OsCSN1 and found that the mutant of OsCSN1 with 102 amino acids missing at the N-terminus showed insensitivity to red light in terms of the embryonic sheath, stem elongation, and main-root elongation. Moreover, the mutant was able to produce, develop, and bear fruit normally. The research results indicate that OsCSN1 is a negative regulator of stem elongation in rice seedlings regulated by red light. Under red-light treatment, OsCSN1 assembles into CSN, which degrades SLR1 through de NEDDylation, affecting PIL11 activity and ultimately inhibiting stem elongation. OsCSN1 also plays an important regulatory role in the inhibition of rice embryonic sheath elongation under red light. By regulating the degradation of SLR1 and PIL14 through the ubiquitin/26S protease pathway, the elongation of the embryonic sheath is ultimately inhibited. OsCSN1 forms a COP9 complex and is modified with RUB/NEDD8 of the E3 ligase of CUL1 to promote the degradation of SLR1 and PIL14, ultimately affecting the elongation of the embryonic sheath. The regulatory domain is located at the N-terminus of CSN1.

Evaluation of the involvement of HSC70 gene in the growth and development of tomato

Tomato is one of the high-value agricultural crops. The HSP70 gene family is thought to play an important role in plant tolerance to various environmental factors. A family member known as HSC70 is predicted to be involved in plant growth and development, however, its biological functions have not been demonstrated clearly. This study was conducted with the aim to characterise the HSC70 gene in tomato plants and evaluate its contribution to tomato growth through phenotypic analysis of plant mutants with defects in the HSC70 gene. The research results showed that nonsense mutationin the HSC70 gene caused short plant and reduced the seed germination rate and fruit set rate of tomato. However, these missense mutations did not change these phenotypes significantly. The leaf shape, leaf structure, and flowering time of tomato were not affected by the HSC70 mutations. These findings provided preliminary insights for further study on the role of the HSC70gene in the germination, elongation, and fruit setting of tomato plants.

BnVP1, a novel vacuolar H+ pyrophosphatase gene from Boehmeria nivea confers cadmium tolerance in transgenic Arabidopsis.

Plants have developed precise defense mechanisms against cadmium (Cd) stress, with vacuolar compartmentalization of Cd2+ being a crucial process in Cd detoxification. The transport of Cd into vacuoles by these cation / H+ antiporters is powered by the pH gradient created by proton pumps. In this study, the full-length cDNA of a vacuolar H+-pyrophosphatase (V-PPase) gene from Boehmeria nivea (ramie), BnVP1, was isolated using the rapid amplification of cDNA ends (RACE) method. The open reading frame (ORF) of BnVP1 is 2292 bp, encoding a 763 amino acid V-PPase protein with 15 predicted transmembrane domains. Sequence alignment and phylogenetic analysis revealed that BnVP1 belongs to the Type I V-PPase family. Quantitative RT-PCR assays demonstrated that BnVP1 expression was significantly higher in ramie roots than in shoots. Cd treatments markedly induced BnVP1 expression in both roots and leaves of ramie seedlings, with a more pronounced effect in roots. Additionally, BnVP1 expression was significantly upregulated by the plant hormone methyl jasmonate (MeJA). Heterologous expression of BnVP1 in transgenic Arabidopsis significantly enhanced V-PPase activity in the roots. The growth performance, root elongation, and total chlorophyll content of transgenic plants with high tonoplast H+-PPase (V-PPase) activity were superior to those of wild-type plants. Overexpression of BnVP1 reduced membrane lipid peroxidation and ion leakage, and significantly increased Cd accumulation in the roots of transgenic Arabidopsis seedlings. This study provides new genetic resources for the phytoremediation of Cd-contaminated farmland.

Anaerobic digestates from cow dung and food waste as fertilizers: Effect on tomato growth and yield

Organic farming systems aim to reduce chemical inputs including fertilizers and ensure sustainable and eco-friendly production while recycling local renewable resources such as organic wastes. The aim of this study is to investigate the effect of two anaerobic digestates on tomato yield and growth in open field conditions. Digestates consisting of cattle dung and food waste from a 15 m3 demountable digester and fixed-dome digester, respectively, were applied to tomato cultivation using tree fertilization treatments: 1) raw (PD100) and 2) diluted up to 50% (PD50) cattle dung digestate, 3) food waste digestate (DD), and an unfertilized treatment (control) for 21 weeks. The results showed that tomato plants fertilized with PD50 and DD were significantly higher (+34% and +33%, respectively) compared to the control and PD100 (p<0.05), and all digestate treatments significantly (p<0.05) enhanced plant elongation compared to the control. This study suggests that anaerobic digestates can be a helpful alternative in the perspective of partial substitution of chemical fertilizers for sustainable tomato production.

Magic Blue Light: A Versatile Mediator of Plant Elongation.

Blue light plays an important role in regulating plant elongation. However, due to the limitations of older lighting technologies, the responses of plants to pure blue light have not been fully studied, and some of our understandings of the functions of blue light in the literature need to be revisited. This review consolidates and analyzes the diverse findings from previous studies on blue-light-mediated plant elongation. By synthesizing the contrasting results, we uncover the underlying mechanisms and explanations proposed in recent research. Moreover, we delve into the exploration of blue light-emitting diodes (LEDs) as a tool for manipulating plant elongation in controlled-environment plant production, highlighting the latest advancements in this area. Finally, we acknowledge the challenges faced and outline future directions for research in this promising field. This review provides valuable insights into the pivotal role of blue light in plant growth and offers a foundation for further investigations to optimize plant elongation using blue light technology.

Integrated transcriptomic and metabolomic analysis reveals the potential mechanisms underlying indium-induced inhibition of root elongation in wheat plants

Soil contamination by indium, an emerging contaminant from electronics, has a negative impact on crop growth. Inhibition of root growth serves as a valuable biomarker for predicting indium phytotoxicity. Therefore, elucidating the molecular mechanisms underlying indium-induced root damage is essential for developing strategies to mitigate its harmful effects. Our transcriptomic findings revealed that indium affects the expression of numerous genes related to cell wall composition and metabolism in wheat roots. Morphological and compositional analysis revealed that indium induced a 2.9-fold thickening and a 17.5 % increase in the content of cell walls in wheat roots. Untargeted metabolomics indicated a substantial upregulation of the phenylpropanoid biosynthesis pathway. As the major end product of phenylpropanoid metabolism, lignin significantly accumulated in root cell walls after indium exposure. Together with increased lignin precursors, enhanced activity of lignin biosynthesis-related enzymes was observed. Moreover, analysis of the monomeric content and composition of lignin revealed a significant enrichment of p-hydroxyphenyl (H) and syringyl (S) units in root cell walls under indium stress. The present study contributes to the existing knowledge of indium toxicity. It provides valuable insights for developing sustainable solutions to address the challenges posed by electronic waste and indium contamination on agroecosystems.

INFLUENCE OF ROW SPACING ON THE PRODUCTIVITY OF MAIZE HYBRIDS OF DIFFERENT MATURITY GROUPS

Growing corn is a complex process, the success of which depends on compliance with the cultivation technology. Increasing the productivity of modern maize hybrids without incurring high cultivation costs is possible primarily by optimizing the plant nutrition area by using different row spacing. The research on this topic was conducted during 2021-2022 in the conditions of Organic-D LLC in the village of Sutisky. We have found that row spacing significantly affects the complex of economically valuable traits and productivity of corn plants. Reducing the row spacing from 70 to 45 cm, especially for mid-early and mid-season maize hybrids, increases the competition of plants for light and promotes plant elongation and linear growth by 2-5 cm. Increasing the row spacing from 45 to 70 cm has a positive effect on increasing the length and weight of cobs in the group of medium-early and medium-ripening maize hybrids, causing an increase in the number of rows of grains by 1.2-1.3 pcs. For the group of early maturing hybrids, the change in row spacing did not have a significant effect on cob length and cob weight. The largest number of cobs at a row spacing of 45 cm was formed by early ripe corn hybrids Dniprovskyi 181 SV - 76.3 thousand pieces per hectare and DMS Coral - 75.8 thousand pieces per hectare. The use of row spacing of 70 cm for the mid-early and mid-season group contributes to the formation of the largest number of cobs for the mid-season hybrid - Vizir - 84.1 thousand units per hectare and the mid-early Bogatyr - 81.8 thousand units per hectare. Extending the duration of the growing season in the studied maize hybrids requires the use of row spacing of 70 cm, while the number of grains in a number of medium-early and medium-ripening hybrids increases by 4.2-9.5 pcs. The increase in yield due to the use of row spacing of 70 cm was significant for mid-early and mid-season hybrids and amounted to 0.36-2.07 t/ha, compared to the row spacing of 45 cm.

Modulation of warm temperature-sensitive growth using a phytochrome B dark reversion variant, phyB[G515E], in Arabidopsis and rice

IntroductionAmbient temperature-induced hypocotyl elongation in Arabidopsis seedlings is sensed by the epidermis-localized phytochrome B (phyB) and transduced into auxin biosynthesis via a basic helix-loop-helix transcription factor, phytochrome-interacting factor 4 (PIF4). Once synthesized, auxin travels down from the cotyledons to the hypocotyl, triggering hypocotyl cell elongation. Thus, the phyB–PIF4 module involved in thermosensing and signal transduction is a potential genetic target for engineering warm temperature-insensitive plants. ObjectivesThis study aims to manipulate warm temperature-induced elongation of plants at the post-translational level using phyB variants with dark reversion, the expression of which is subjected to heat stress. MethodsThe thermosensitive growth response of Arabidopsis was manipulated by expressing the single amino acid substitution variant of phyB (phyB[G515E]), which exhibited a lower dark reversion rate than wild-type phyB. Other variants with slow (phyB[G564E]) or rapid (phyB[S584F]) dark reversion or light insensitivity (phyB[G767R]) were also included in this study for comparison. Warming-induced transient expression of phyB variants was achieved using heat shock-inducible promoters. Arabidopsis PHYB[G515E] and PHYB[G564E] were also constitutively expressed in rice in an attempt to manipulate the heat sensitivity of a monocotyledonous plant species. ResultsAt an elevated temperature, Arabidopsis seedlings transiently expressing PHYB[G515E] under the control of a heat shock-inducible promoter exhibited shorter hypocotyls than those expressing PHYB and other PHYB variant genes. This warm temperature-insensitive growth was related to the lowered PIF4 and auxin responses. In addition, transgenic rice seedlings expressing Arabidopsis PHYB[G515E] and PHYB[G564E] showed warm temperature-insensitive shoot growth. ConclusionTransient expression of phyB variants with altered dark reversion rates could serve as an effective optogenetic technique for manipulating PIF4–auxin-mediated thermomorphogenic responses in plants.

A single nucleotide mutation in ClphyB gene is associated with a short lateral branch phenotype in watermelon

The plant branching habit is a unique morphological trait of watermelon that regulates the plant architecture as well as crop yield, but the in-depth understanding of molecular regulation of the branching habit in watermelon is less studied. In this experiment, two contrasted watermelon lines with different phenotypes “a normal branching line (GWAS-38) and a mutant short lateral branched (slb) line” were crossed to derive the bi-parental F2 mapping populations. Genetic segregation analysis of collected phenotypic data depicted a good-fit 3:1 segregating ratio, which indicated that the slb locus in the mapping population was regulated by one recessive gene. A bulk segregant sequencing analysis (BSA-seq) method and genetic linkage mapping with F2 mapping populations (336 plants) preliminary identified the 1.63 Mbp region on chromosome 5. Fine genetic mapping with an expanded F2 mapping population (1020 plants) narrowed down the candidate slb locus to a 25.355 kb interval with two predicted genes. The sequence variations indicated a 1 bp deletion (A→-) causing a truncated protein lacking the conserved domains for the phytochrome PAS2 structural domain and HATPase structural domain in the mutant slb line, which was also co-segregated with the short lateral branched phenotype. The haplotype analysis and gene expression analysis suggested that the Cla97C05G088180.1 gene encoding phytochrome B, is the major gene regulating the phenotype of short lateral branched trait in mutant slb line. Further, CRISPR/Cas9-mediated mutation of CsphyB led to hypocotyl elongation, reduced leaf angle, and inhibited branch elongation, suggesting that CsphyB is mainly responsible for regulation of branch elongation in cucumber plants. To the best of our knowledge, we first time reported the vital molecular characterization and cloning of the ClphyB gene regulating branch elongation in watermelon. We believe that our results would provide beneficial genetic insights for understanding the possible roles of ClphyB in the architecture watermelon plant.