Wheat Spike Development Research Articles

A new scale for the assessment of wheat spike morphogenesis

The period prior to anthesis determines to a great extent the yield in wheat by modifying the number of fertile florets and hence the number of grains per spike. For an easy and accurate identification of this period to researchers and cereal growers a simple numerical scale of wheat spike development is proposed. It includes 20 distinct stages, starting from the apex transition stage and ending just prior to heading, with the stages being separated by similar-sized steps in thermal time to produce a continuous scale. The scale describes the whole process of wheat apical development and is convenient (e.g. uses easily detectable characters without great magnification, such as the development of awns, lemmas and glumes) and precise (e.g. uses combination of more stable characters, such as pistil and stamen development as well as the sequence of floret initiation, in order to accurately assess the development of the spike). The proposed scale was used to describe the development of the durum wheat cultivar ‘‘Mexicali 81’’ during two seasons. The meteorological conditions during the different cultivation seasons affected the onset and the duration of the spike developmental phases. Additionally, a variation was observed concerning the synchronisation between spike morphogenesis and plant external developmental phases (e.g. tillering, jointing and boot). The advantages of the new scale with respect to the already existing ones are discussed.

Cullin, a component of the SCF complex, interacts with TaRMD5 during wheat spike development

Cullin, a major component of the SKP1-cullin-F box protein (SCF) complex, is a scaffold protein that binds to both SKP1 and RBX1 for selective protein degradation through the ubiquitin proteasome system. In order to study the role of cullin in common wheat, we isolated TaCullin (Cullin gene from Triticum aestivum) from wheat spike cDNA. TaCullin was expressed during all spike/grain developmental stages and in high amounts during early spike/grain development. The TaCullin gene is located on the chromosome arm 2DL. Our results suggest that unneddylated TaCullin is located in the nucleus. Based on previous proposals of Cullin-SKP1 interactions, we examined the interaction between TaCullin and SKP1-like protein (TaSKP) families by using a yeast two-hybrid approach. Yeast cotransformation demonstrated that the N-terminus of TaCullin physically interacts with TaSKP proteins. Using the yeast two-hybrid screen, we identified potential TaCullin-interacting proteins in a wheat spike library. Among the 9 clones that were identified as potential interacting partners of TaCullin, we identified E3-like ubiquitin ligase, targeting fructose-1,6-bisphosphatase (RMD5) homolog A-like protein. The interaction between TaCullin and the TaRMD5 homolog A-like protein was specifically mediated through the C-terminus of TaCullin. The results of bimolecular fluorescence complementation assay indicated that TaCullin-TaRMD5 is localized in the plasma membrane and cytoplasm. In this study, we present that TaRMD5, such as RING box protein 1 (RBX1), has the potential to interact with TaCullin, depending on the developmental stage and particular organ tissues analyzed.

A proteomic study of spike development inhibition in bread wheat

Spike development in wheat is a complicated development process and determines the wheat propagation and survival. We report herein a proteomic study on the bread wheat mutant strain 5660M underlying spike development inhibition. A total of 121 differentially expressed proteins, which were involved in cold stress response, protein folding and assembly, cell-cycle regulation, scavenging of ROS, and the autonomous pathway were identified using MS/MS and database searching. We found that cold responsive proteins were highly expressed in the mutant in contrast to those expressed in the wild-type line. Particularly, the autonomous pathway protein FVE, which modulates flowering, was dramatically downregulated and closely related to the spike development inhibition phenotype of 5660M. A quantitative RT-PCR study demonstrated that the transcription of the FVE and other six genes in the autonomous pathway and downstream flowering regulators were all markedly downregulated. The results indicate that spike development of 5660M cannot complete the floral transition. FVE might play an important role in the spikes development of the wheat. Our results provide the theory basis for studying floral development and transition in the reproductive growth period, and further analysis of wheat yield formation.

Wheat F-box protein recruits proteins and regulates their abundance during wheat spike development

F-box proteins, components of the Skp1-Cullin1-F-box (SCF) protein E3 ubiquitin ligase complex, serve as the variable component responsible for substrate recognition and recruitment in SCF-mediated proteolysis. F-box proteins interact with Skp1 through the F-box motif and with ubiquitination substrates through C-terminal protein interaction domains. F-box proteins regulate plant development, various hormonal signal transduction processes, circadian rhythm, and cell cycle control. We isolated an F-box protein gene from wheat spikes at the onset of flowering. The Triticum aestivum cyclin F-box domain (TaCFBD) gene showed elevated expression levels during early inflorescence development and under cold stress treatment. TaCFBD green fluorescent protein signals were localized in the cytoplasm and plasma membrane. We used yeast two-hybrid screening to identify proteins that potentially interact with TaCFBD. Fructose bisphosphate aldolase, aspartic protease, VHS, glycine-rich RNA-binding protein, and the 26S proteasome non-ATPase regulatory subunit were positive candidate proteins. The bimolecular fluorescence complementation assay revealed the interaction of TaCFBD with partner proteins in the plasma membranes of tobacco cells. Our results suggest that the TaCFBD protein acts as an adaptor between target substrates and the SCF complex and provides substrate specificity to the SCF of ubiquitin ligase complexes.

Simulating winter wheat spike development and growth

Mechanistic crop simulation models can aid in integrating and directing research, and in improving farm management strategies. Information derived from recent research on spike development and growth of winter wheat ( Triticum aestivum L.) was incorporated into a submodel, SPIKEGRO, and added to an existing model called SHOOTGRO. This manuscript discusses the SPIKEGRO submodel. SPIKEGRO emphasizes the reproductive functioning of the shoot apex. The complete developmental sequence of the shoot apex is outlined and quantified. All developmental events and growth stages are predicted, most using the phyllochron approach. Spikelet and floret primordium initiation, growth, and abortion; ovule fertilization and growth; and rachis and chaff growth are simulated on morphologically-identified culms. The phyllochron interval, rather than growing degree-days, is used throughout the model to increase flexibility in predicting yearly and within-stand variation in development. Up to six cohorts of plants are simulated simultaneously from time of emergence, using a daily time step. Initial inputs consist of general agronomic information such as planting date, density, and depth, site latitude, cultivar height-class, soil water and N concentration, and soil characteristics (e.g. bulk density, organic carbon, parameters for a water-release curve). Cultivar differences, if known, can be incorporated by changing the input parameter file. Validation results and sensitivity analysis suggested six modifications that should improve model realism and predictions. Most of the modifications are easy corrections of simplified algorithms. SPIKEGRO integrates aboveground development and growth of individual plant components into one simulation. The model is useful in estimating development and growth throughout the growing season, and in predicting all stages of shoot apex development critical in scheduling cultural practices.

Feature of Barley and Wheat Spike Development in Southern Area of Iwate Prefecture. - Difference of late Seeding on the Spike development of wheat -

Feature of Barley and Wheat Spike Development in Southern Area of Iwate Prefecture. - Difference of late Seeding on the Spike development of wheat -

Feature of Barley and Wheat Spike Development in Southern Area of Iwate Prefecture

Feature of Barley and Wheat Spike Development in Southern Area of Iwate Prefecture