Duration Of Elongation Research Articles

Interaction of the cyclin-dependent kinase inhibitor GhKRP6 with RING-Type E3 ligase influences the fiber length in Upland cotton

Upland cotton (Gossypium hirsutum L.) is the major crop producing renewable fiber for textiles. Cotton fiber length is an economically important trait that affects the quality of the yarn. The Upland cotton multi-parent advanced generation intercross (MAGIC) population was developed for genetics research to understand how fiber traits can be improved without reducing fiber yield. A genome-wide association study of the MAGIC population identified a significant fiber length QTL on Chromosome D11 (qFL-D11–1). To understand how the qFL-D11–1 regulates fiber length, we developed F5 lines by crossing the longest and the shortest fiber recombinant inbred lines (RILs) of the MAGIC population to establish lines with parental haplotypes at the qFL-D11–1 but segregating for other loci. The F5 lines and parental RILs were sequenced to detect exchanges from parents' genomic regions in the progeny. One segregating genomic region in the F5 lines coincided with qFL-D12–1, which additively affected fiber length. Correlation analysis of the expression patterns of genes from the two QTLs with the fiber lengths in the MAGIC population showed the highest correlation of the RING-type ubiquitin E3 ligase (GhUbE3) from qFL-D12–1. Kip-related protein-6 (KRP6) is the candidate gene from the qFL-D11–1. A yeast two-hybrid and bimolecular fluorescence complementation assays demonstrated a physical interaction between GhKRP6 (Ghir_D11G020340) and GhUbE3 (Ghir_D12G006080). RNAseq showed that the GhUbE3 expression is reciprocal to the interacting GhKRP6 during fiber development. Virus-induced gene silencing (VIGS) of GhKRP6 increased fiber length. The data indicates that GhUbE3 controls the dose of GhKRP6's inhibitory activity and, therefore, the duration of fiber elongation.

R2R3 MYB Transcription Factor GhMYB201 Promotes Cotton Fiber Elongation via Cell Wall Loosening and Very-Long-Chain Fatty Acid Synthesis.

Cotton fiber is the leading natural textile material, and fiber elongation plays an essential role in the formation of cotton yield and quality. Although a number of components in the molecular network controlling cotton fiber elongation have been reported, a lot of players still need to be functionally dissected to understand the regulatory mechanism of fiber elongation comprehensively. In the present study, an R2R3-MYB transcription factor gene, GhMYB201, was characterized and functionally verified via CRISPR/Cas9-mediated gene editing. GhMYB201 was homologous to Arabidopsis AtMYB60, and both coding genes (GhMYB201At and GhMYB201Dt) were preferentially expressed in elongating cotton fibers. Knocking-out of GhMYB201 significantly reduced the rate and duration of fiber elongation, resulting in shorter and coarser mature fibers. It was found that GhMYB201 could bind and activate the transcription of cell wall loosening genes (GhRDLs) and also β-ketoacyl-CoA synthase genes (GhKCSs) to enhance very-long-chain fatty acid (VLCFA) levels in elongating fibers. Taken together, our data demonstrated that the transcription factor GhMYB201s plays an essential role in promoting fiber elongation via activating genes related to cell wall loosening and VLCFA biosynthesis.

Dynamic Phytomeric Growth Contributes to Local Adaptation in Barley.

Vascular plants have segmented body axes with iterative nodes and internodes. Appropriate node initiation and internode elongation are fundamental to plant fitness and crop yield; however, how these events are spatiotemporally coordinated remains elusive. We show that in barley (Hordeum vulgare L.), selections during domestication have extended the apical meristematic phase to promote node initiation, but constrained subsequent internode elongation. In both vegetative and reproductive phases, internode elongation displays a dynamic proximal-distal gradient, and among subpopulations of domesticated barleys worldwide, node initiation and proximal internode elongation are associated with latitudinal and longitudinal gradients, respectively. Genetic and functional analyses suggest that, in addition to their converging roles in node initiation, flowering-time genes have been repurposed to specify the timing and duration of internode elongation. Our study provides an integrated view of barley node initiation and internode elongation and suggests that plant architecture should be recognized as a collection of dynamic phytomeric units in the context of crop adaptive evolution.

Sink Strength During Sugarcane Culm Growth: Size Matters

Sugarcane growth and its subsequent yield are linked to plant height. The increase in sugarcane height is controlled by elongation of the top 6 to 7 internodes. The elongation of the internodes can be significantly reduced by an application of the Trinexapac-ethyl (Moddus®) which is a known disruptor of GA synthesis. In this study, the growth and composition of the internodes were analysed following the treatment. We found that the strong inhibitory effect of Moddus® on internode size was due to a strongly suppressed rate of internode elongation, with no effect on the duration of the elongation period. The Moddus® inhibition of internode elongation was not due to a lack of an osmotic potential gradient but probably reflects a higher pressure potential of the tissue. A consequence of the reduced internode size was a significant reduction in carbon flow (sink strength) of the internode. It was not only the rate of internode growth that was altered by Moddus®, but also partitioning within the internode. Partitioning of carbon into components other than the soluble sugars and cell wall was significantly reduced by the Moddus® treatment. The high reducing sugar content in the Moddus® treatment suggests that sucrose mobilisation (hydrolysis by invertases and cleavage by sucrose synthase) might, like the duration of elongation, be controlled by thermal time. No accumulation of reducing sugars was evident in the control internodes probably due to the rapid mobilisation to other cellular processes. Sucrose accumulation in the internode reflected a cessation of sugar utilisation to support growth and maintenance.

Índice de nutrição nitrogenada e morfogênese em papuã na Depressão Central do Rio Grande do Sul

ABSTRACT: This study assessed the nitrogen nutrition index, morphogenic characteristics and tiller structure of Alexandergrass (Urochloaplantaginea (LINK) Hitch) pasture submitted to different nitrogen (N) levels (zero, 150 or 300 kg ha-1 of N). The experimental design was entirely randomized with repeated measures arrangement. The experimental animals were Angus heifers under rotational stocking grazing method. The number of animals was variable to keep 30±5 cm post-grazing sward height. Nitrogen nutrition index increased linearly according N levels (Ŷ = 59.8 + 0.1216N; P < 0.0001; r²=0.53). The leaf appearance rate adjusted to a positive linear regression model according the thermal sum (TS) with zero of N (Ŷ0N = 0.0077 + 0.0000087TS; P = 0.0308; r² = 0.72) and 150 kg ha-1 of N (Ŷ150N = 0.0020 + 0.000021 TS; P = 0.0022; r² = 0.92). The use of 300 kg ha-1 of N did not alter the leaf appearance rate (0.0124 leaf degree-days-1). The use of up to 300 kg ha-1 of N increases the Alexandergrass nitrogen content. The leaf appearance rate in Alexandergrass is modified using N while the morphogenic characteristics leaf expansion, stem expansion, phyllochron, leaf lifespan, leaf elongation duration and tiller structure are not altered by N utilization.

Viral tropism for the testis and sexual transmission.

The mammalian testis adopts an immune privileged environment to protect male germ cells from adverse autoimmune reaction. The testicular immune privileged status can be also hijacked by various microbial pathogens as a sanctuary to escape systemic immune surveillance. In particular, several viruses have a tropism for the testis. To overcome the immune privileged status and mount an effective local defense against invading viruses, testicular cells are well equipped with innate antiviral machinery. However, several viruses may persist an elongated duration in the testis and disrupt the local immune homeostasis, thereby impairing testicular functions and male fertility. Moreover, the viruses in the testis, as well as other organs of the male reproductive system, can shed to the semen, thus allowing sexual transmission to partners. Viral infection in the testis, which can impair male fertility and lead to sexual transmission, is a serious concern in research on known and on new emerging viruses. To provide references for our scientific peers, this article reviews research achievements and suggests future research focuses in the field.

Distinguishing Unique Earthquakes with Overlapping Signals in Oklahoma

AbstractDuring routine operations monitoring Oklahoma earthquakes, we found that certain earthquakes occurred closely both in space and time and had overlapping phases at the recording stations. Through further scrutiny and analysis, we determined that rather than being distinctly different earthquakes, some of the earthquakes exhibited multiphase arrivals and longer than expected coda due to unique ray paths that encounter impedance contrasts such as at the sedimentary rock-basement. Of course, some of these events truly were distinct events, which we term overlapping earthquakes, for which perceived coda duration overlaps and obscures the phase arrivals of the second event due to the source proximity in both time and space. We detail our classification scheme to separate the local earthquakes in Oklahoma as single, overlapping earthquakes, or those associated with multiphase arrivals. We forward model seismic wave propagation in a 2D crustal model and develop a methodology that utilizes waveform correlation to distinguish phases from overlapping earthquakes to those from crustal reverberations. Duration analysis shows a more elongated duration, qualitatively similar to the duration produced by overlapping earthquakes, at the sites where multiphase arrivals are observed.

Abstract 357: Characterization of KRas pathway inhibitors in 2D and 3D screening formats

Abstract The KRas/Raf/MEK signalling axis has been identified to play a critical role in the formation of cancer, resulting in several investigational new drugs targeting this pathway. Identification of appropriate drugs is hampered, however, by the assumption that a three-dimensional setting may be required to observe significant inhibitory effects, possibly due to alternate gene expression and protein activity in such a “closer-to-physiology” setting. In order to explore that topic, in the current study we have made use of our 140 cell lines (CL)-2D proliferation panel (3 days incubation) and our 100CL-3D soft agar panel (> 7 days incubation). On these platforms, we have compared inhibitors targeting the KRas/Raf/MEK pathway via either KRas:SOS interaction (e.g. BI3406), the KRas mutation at G12C (e.g. AMG510), or Raf-kinase (e.g. AZ628) and MEK1/2-kinase activity (e.g. AZD6244). It showed that especially the Raf- and MEK kinase inhibitors exhibited significantly enhanced potency in the 3D soft agar setting in the majority of the cell lines tested. The other inhibitors also showed an increased potency under soft agar conditions, however, on clearly fewer cell lines and usually not as strongly. For all kinds of inhibitors tested, the most significant changes in potency were associated with enhanced efficacy as observed by stronger cell death induction. Differences may be attributable to three-dimensional growth, but also to the elongated duration of the soft agar assay. For selected conditions, we addressed this topic by analyzing the inhibitor impact on 3D spheroid growth after shorter incubation times. Our results show that 3D growth analysis either in the soft agar or spheroid setting clearly supports the development of KRas/Raf/MEK pathway inhibitors. Citation Format: Katharina Schaich, Daniel Feger, Oliver Siedentopf, Sarah Ulrich, Jan Erik Ehlert. Characterization of KRas pathway inhibitors in 2D and 3D screening formats [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 357.

Trade-offs among transcription elongation rate, number, and duration of ubiquitous pauses on highly transcribed bacterial genes.

In this paper, we study the limitations imposed on the transcription process by the presence of short ubiquitous pauses and crowding. These effects are especially pronounced in highly transcribed genes such as ribosomal genes (rrn) in fast growing bacteria. Our model indicates that the quantity and duration of pauses reported for protein-coding genes is incompatible with the average elongation rate observed in rrn genes. When maximal elongation rate is high, pause-induced traffic jams occur, increasing promoter occlusion, thereby lowering the initiation rate. This lowers average transcription rate and increases average transcription time. Increasing maximal elongation rate in the model is insufficient to match the experimentally observed average elongation rate in rrn genes. This suggests that there may be rrn-specific modifications to RNAP, which then experience fewer pauses, or pauses of shorter duration than those in protein-coding genes. We identify model parameter triples (maximal elongation rate, mean pause duration time, number of pauses) which are compatible with experimentally observed elongation rates. Average transcription time and average transcription rate are the model outputs investigated as proxies for cell fitness. These fitness functions are optimized for different parameter choices, opening up a possibility of differential control of these aspects of the elongation process, with potential evolutionary consequences. As an example, a gene's average transcription time may be crucial to fitness when the surrounding medium is prone to abrupt changes. This paper demonstrates that a functional relationship among the model parameters can be estimated using a standard statistical analysis, and this functional relationship describes the various trade-offs that must be made in order for the gene to control the elongation process and achieve a desired average transcription time. It also demonstrates the robustness of the system when a range of maximal elongation rates can be balanced with transcriptional pause data in order to maintain a desired fitness.

Turgor-time controls grass leaf elongation rate and duration under drought stress.

The process of leaf elongation in grasses is characterized by the creation and transformation of distinct cell zones. The prevailing turgor pressure within these cells is one of the key drivers for the rate at which these cells divide, expand and differentiate, processes that are heavily impacted by drought stress. In this article, a turgor-driven growth model for grass leaf elongation is presented, which combines mechanistic growth from the basis of turgor pressure with the ontogeny of the leaf. Drought-induced reductions in leaf turgor pressure result in a simultaneous inhibition of both cell expansion and differentiation, lowering elongation rate but increasing elongation duration due to the slower transitioning of cells from the dividing and elongating zone to mature cells. Leaf elongation is, therefore, governed by the magnitude of, and time spent under, growth-enabling turgor pressure, a metric which we introduce as turgor-time. Turgor-time is able to normalize growth patterns in terms of varying water availability, similar to how thermal time is used to do so under varying temperatures. Moreover, additional inclusion of temperature dependencies within our model pioneers a novel concept enabling the general expression of growth regardless of water availability or temperature.

Effects of Quality Control Circle Activities for Intravenous Cannula Placement Using Deming Cycle Management: A Case-Controlled Study

The present study aimed to explore the effectiveness of quality control circle (QCC) activities under the guidance of the Deming cycle Management for improving intravenous (IV) cannula placement. A total of 1,035 patients who underwent IV cannula placement from March 2019 to June 2019 in the Department of Hepatobiliary Surgery and Department of Renal and Thoracic Surgery of our hospital were enrolled as the control group, and 1,437 patients who underwent IV cannula placement in the same places as above but from July 2019 to December 2019 were enrolled as the test group. A between-group comparison was performed on intangible and tangible outcomes (duration of IV cannula placement, complications, patient awareness rate of maintenance knowledge of IV cannula, patient satisfaction rate with nursing staff, nurse skills in IV cannula infusion, and maintenance). After QCC activities were implemented, the scores of 11 QCC members in the five aspects of QCC technique application, communication and coordination, sense of responsibility and honor, motivation, and problem-solving ability all improved compared with those before the activities (p < 0.05), and the duration of IV cannula placement in the test group was 70.22 ±48.33 h, which was longer (p < 0.05) than the 60.59±41.9 h of the control group. The test group had a significantly lower (p < 0.05) rate of complications (12.9%, 12.6%, and 1.3% for extravasation, phlebitis, and cannula obstruction, respectively) than the control group (30.0%, 11.4%, and 4.1% for blood oozing, phlebitis, and cannula obstruction respectively); the patient awareness rate of maintenance knowledge of IV cannula and patient satisfaction rate with nursing staff in the test group were 90% and 96.3%, respectively, which were significantly higher (p < 0.05) than the 82.4% and 81.5% in the control group. The scores of nurse skills in IV cannula infusion and maintenance in the test group were 90.5 ±1.3 and 93.6 ±2.0, respectively, which were significantly higher (p < 0.05) than the 85.5 ±2.7 and 81 ±1.0 in the control group. The implementation of QCC activities under the guidance of the Deming cycle Management in IV cannula placement improves the ability of the department’s nursing team to identify, analyze, and solve problems, which is favorable for continuous improvement of nursing quality, leading to an elongated duration of IV cannula placement, reduced rate of complications, and improved patient satisfaction rate with nursing services.

Examining the potential of calcined oyster shell waste as additive in high volume slag cement

The present study investigates the effect of calcined waste oyster shell powder as additive on the fresh, hardened and microstructural properties of high volume slag cement. The results provide that addition of calcined oyster shell powder enhanced the early age compressive strength. The hydration of calcined oyster shell powder resulted in additional portlandite formation during the initial reaction stage. The observations drawn from porosity measurements indicated that calcined oyster shell powder decreased the porosity of binder matrix at early and elongated duration of curing. Furthermore, by 29Si NMR it was observed that the hydration of high volume slag cement was also benefited by calcined oyster shell powder as indicated by increased degree of hydration and chain length. However, excess addition of calcined oyster shell powder caused decreased compressive strength development. Considering the results, calcined oyster shell powder can be used as additive in high volume slag cement.

Ethephon-regulated maize internode elongation associated with modulating auxin and gibberellin signal to alter cell wall biosynthesis and modification

Ethephon efficiently regulates plant growth to modulate the maize (Zea mays L.) stalk strength and yield potential, yet there is little information on how ethylene governs a specific cellular response for altering internode elongation. Here, the internode elongation kinetics, cell morphological and physiological properties and transcript expression patterns were investigated in the ethephon-treated elongating internode. Ethephon decreased the internode elongation rate, shortened the effective elongation duration, and advanced the growth process. Ethephon regulated the expression patterns of expansin and secondary cell wall-associated cellulose synthase genes to alter cell size. Moreover, ethephon increased the activities and transcripts level of phenylalanine ammonia-lyase and peroxidase, which contributed to lignin accumulation. Otherwise, ethephon-boosted ethylene evolution activated ethylene signal and increased ZmGA2ox3 and ZmGA2ox10 transcript levels while down-regulating ZmPIN1a, ZmPIN4 and ZmGA3ox1 transcript levels, which led to lower accumulation of gibberellins and auxin. In addition, transcriptome profiles confirmed previous results and identified several transcription factors that are involved in the ethephon-modulated transcriptional regulation of cell wall biosynthesis and modification and responses to ethylene, gibberellins and auxin. These results indicated that ethylene-modulated auxin and gibberellins signaling mediated the transcriptional operation of cell wall modification to regulate cell elongation in the ethephon-treated maize internode.

Performance and feed intake of beef heifers on rotational grazing of natural grassland receiving protein and energy supplement in cool season

ABSTRACT: The aim of this study was to evaluate the performance and feed intake of grazing beef heifers on two grazing intervals determined by thermal sum related to leaf elongation duration during cool season on natural grasslands. A complete randomized block design experiment with two treatments and three replications was conducted from May to September 2011 in the central part of the state of Rio Grande do Sul, Brazil. The treatments were two thermal sums calculated at 375 and 750 degrees-days (DD) to determine the intervals between grazing periods in a rotational grazing system. Thirty six beef heifers with average age of 18 months old and (initial body weight = 220±14kg) were used, all heifers received ground corn supplement at a rate of 5g kg-1 of body weight per day, at 2p.m., throughout the experiment and had free access to mineral and protein supplementation (450g kg-1 of CP). Similar average daily gain (ADG), beef production gain (BPG) and feed intake (FI), were obtained in both treatments. Leaf elongation duration is an alternative grazing management tool for improved animal production and to increase animal stocking rate.

Growth rate rather than growth duration drives growth heterosis in maize B104 hybrids.

Research in maize is often performed using inbred lines that can be readily transformed, such as B104. However, because the B104 line flowers late, the kernels do not always mature before the end of the growing season, hampering routine seed yield evaluations of biotech traits introduced in B104 at many geographical locations. Therefore, we generated five hybrids by crossing B104 with the early‐flowering inbred lines CML91, F7, H99, Mo17, and W153R and showed in three consecutive years that the hybrid lines proved to be suitable to evaluate seed yield under field conditions in a temperate climate. By assessing the two main processes driving maize leaf growth, being rate of growth (leaf elongation rate or LER) and the duration of growth (leaf elongation duration or LED) in this panel of hybrids, we showed that leaf growth heterosis was mainly the result of increased LER and not or to a lesser extent of LED. Ectopic expression of the transgenes GA20‐oxidase (GA20‐OX) and PLASTOCHRON1 (PLA1), known to stimulate the LER and LED, respectively, in the hybrids showed that leaf length heterosis can be stimulated by increased LER, but not by LED, indicating that LER rather than LED is the target for enhancing leaf growth heterosis.

Simulative Global Warming Negatively Affects Cotton Fiber Length through Shortening Fiber Rapid Elongation Duration

Global warming could possibly increase the air temperature by 1.8–4.0 °C in the coming decade. Cotton fiber is an essential raw material for the textile industry. Fiber length, which was found negatively related to the excessively high temperature, determines yarn quality to a great extent. To investigate the effects of global warming on cotton fiber length and its mechaism, cottons grown in artificially elevated temperature (34.6/30.5 °C, Tday/Tnight) and ambient temperature (31.6/27.3 °C) regions have been investigated. Becaused of the high sensitivities of enzymes V-ATPase, PEPC, and genes GhXTH1 and GhXTH2 during fiber elongation when responding to high temperature stress, the fiber rapid elongation duration (FRED) has been shortened, which led to a significant suppression on final fiber length. Through comprehensive analysis, Tnight had a great influence on fiber elongation, which means Tn could be deemed as an ideal index for forecasting the degree of high temperature stress would happen to cotton fiber property in future. Therefore, we speculate the global warming would bring unfavorable effects on cotton fiber length, which needs to take actions in advance for minimizing the loss in cotton production.

Monitoring the dynamics of wheat stem elongation: genotypes differ at critical stages

Stem elongation is a critical phase for yield formation in wheat (Triticum aestivum). This study proposes the use of terrestrial laser scanning (TLS) for phenotyping of growth dynamics during wheat stem elongation in high temporal resolution and high throughput in the field. TLS was implemented on a novel field phenotyping platform carrying a cable suspended sensor head moveable in 3D over a 1 ha field. Canopy height was recorded on 335 winter wheat genotypes across two consecutive years. Scans were done in 3-d intervals during the stem elongation phase. Per day, 714 plots (two replications plus checks) were scanned within 3.5 h. The results showed that canopy height increased linearly with thermal time. Based on this linearity, 15 and 95% of final height were used as proxy measures for the onset and termination of stem elongation, respectively. We observed high heritability between 0.76 and 0.91 for the onset, termination and duration of stem elongation. The onset of stem elongation showed a positive covariance with the termination of stem elongation and final height indicating some regulatory dependencies. Yet there was no apparent relationship between onset and duration of stem elongation. Due to its precision, the TLS method allows to measure the dynamics of stem elongation in large sets of genotypes. This in turn offers opportunities to investigate the genetic control of the transitions between early vegetative growth, stem elongation and flowering. Understanding the genetic control of these transitions is an important milestone towards knowledge-based crop improvement.

Modeling final leaf length as a function of carbon availability during the elongation period

Each leaf is both a sink and a source of carbon that determines the growth of plant structure. Therefore, simulation of individual leaf expansion is essential in modeling plant structural growth. Leaf expansion has been often fitted to logistic sigmoidal functions that require initial and final leaf length, and duration of elongation to be known. A different method, based on the compound interest law, determines leaf length using initial length, relative elongation rate and duration of elongation. We aimed to evaluate which factors are most important in explaining final leaf length variability. Elongation of individual leaves on peach shoots was monitored over 21 days. Individual leaf lengths were fitted to logistic functions to determine their initial and final lengths, and durations of elongation in growing degree hours. Parameters that could affect final leaf length were evaluated: shoot characteristics below the leaf, initial length, duration of elongation, and temperature during the initial days after leaf appearance. Final leaf length had significant relationships with leaf area and length of the shoot axis excluding sylleptic branches, but it was not significantly related to initial length or duration of elongation. Total shoot leaf area and temperature during the initial days after leaf appearance also affected final leaf length. Our results showed that final leaf length is mainly determined by factors acting during leaf elongation. Based on these data, we used compound interest law and carbon availability concepts to develop a mechanistic model of final lengths of individual leaves.

Vernalisation and photoperiod sensitivity in wheat: The response of floret fertility and grain number is affected by vernalisation status

The impact of different allelic combinations of VERNALIZATION1 (VRN1) and PHOTOPERIOD1 (PPD1) on the development of reproductive structures, spike dry weight (SDW) and its links to the duration of stem elongation (SE) and yield components was assessed using Near Isogenic Lines (NILs) of the cultivar Sunstate for both genes. Emphasis was on observations on the main shoot and tillers, linking to plant and canopy level in Steinfort at al. (2016). Experiments under controlled and irrigated field conditions relevant to the northern wheat growing region of Australia were designed.In vernalised plants, the number of fertile florets in the main shoot spike was positively related to the number of fertile spikelets, the duration of SE, the SDW at anthesis and the sum of the radiation intercepted during SE, while no associations were found under non vernalised and slow vernalising field conditions. Vernalised plants also produced more grains in the average tiller spike, compared to non vernalised plants, particularly under short days. Both main shoot and tiller grain number per spike contributed to the higher grain number per plant observed in vernalised plants in Steinfort et al. (2016), as spike number was similar. In the field, higher yield of lines with spring alleles of VRN1 was underpinned by longer spikes, with fewer spikelets but more fertile florets per spikelet in the main shoot spike, and more grains per tiller. When non vernalised, winter lines had an apex that grew slower, shorter spikes and higher spikelet density compared to the other genotypes. The utilisation of sensitivity to VRN1 or PPD1 to increase the duration of the SE and the number of fertile florets and grains is a more complex process than originally proposed.

Combined elevated temperature and soil waterlogging stresses inhibit cell elongation by altering osmolyte composition of the developing cotton (Gossypium hirsutum L.) fiber

Soil waterlogging events and high temperature conditions occur frequently in the Yangtze River Valley, yet the effects of these co-occurring stresses on fiber elongation have received little attention. In the current study, the combined effect of elevated temperature (ET) and soil waterlogging (SW) more negatively affected final fiber length (reduced by 5.4%–11.3%) than either stress alone by altering the composition of osmotically active solutes (sucrose, malate, and K+), where SW had the most pronounced effect. High temperature accelerated early fiber development, but limited the duration of elongation, thereby limiting final fiber length. Treatment of ET alone altered fiber sucrose content mainly through decreased source strength and the expression of the sucrose transporter gene GhSUT-1, making sucrose availability the primary determinant of final fiber length under ET. Waterlogging stress alone decreased source strength, down-regulated GhSUT-1 expression and enhanced SuSy catalytic activity for sucrose reduction. Waterlogging treatment alone also limited fiber malate production by down-regulating GhPEPC-1 & −2. However, combined elevated temperature and waterlogging limited primary cell wall synthesis by affecting GhCESAs genes and showed a negative impact on all three major osmotic solutes through the regulation of GhSUT-1, GhPEPC-1 & −2 and GhKT-1 expression and altered SuSy activity, which functioned together to produce a shorter fiber length.