scholarly journals Nitrogen Nutrition Promotes Rhizome Bud Outgrowth via Regulation of Cytokinin Biosynthesis Genes and an Oryza longistaminata Ortholog of FINE CULM 1

2021 ◽  
Vol 12 ◽  
Author(s):  
Kyohei Shibasaki ◽  
Arika Takebayashi ◽  
Nobue Makita ◽  
Mikiko Kojima ◽  
Yumiko Takebayashi ◽  
...  

Oryza longistaminata, a wild rice, can propagate vegetatively via rhizome formation and, thereby, expand its territory through horizontal growth of branched rhizomes. The structural features of rhizomes are similar to those of aerial stems; however, the physiological roles of the two organs are different. Nitrogen nutrition is presumed to be linked to the vegetative propagation activity of rhizomes, but the regulation of rhizome growth in response to nitrogen nutrition and the underlying biological processes have not been well characterized. In this study, we analyzed rhizome axillary bud growth in response to nitrogen nutrition and examined the involvement of cytokinin-mediated regulation in the promotion of bud outgrowth in O. longistaminata. Our results showed that nitrogen nutrition sufficiency promoted rhizome bud outgrowth to form secondary rhizomes. In early stages of the response to nitrogen application, glutamine accumulated rapidly, two cytokinin biosynthesis genes, isopentenyltransferase, and CYP735A, were up-regulated with accompanying cytokinin accumulation, and expression of an ortholog of FINE CULM1, a negative regulator of axillary bud outgrowth, was severely repressed in rhizomes. These results suggest that, despite differences in physiological roles of these organs, the nitrogen-dependent outgrowth of rhizome axillary buds in O. longistaminata is regulated by a mechanism similar to that of shoot axillary buds in O. sativa. Our findings provide a clue for understanding how branched rhizome growth is regulated to enhance nutrient acquisition strategies.

2020 ◽  
Author(s):  
Rongna Wang ◽  
Junjie Qian ◽  
Zhongming Fang ◽  
Jihua Tang

Abstract Background: N is an important macronutrient required for plant development and significantly influences axillary bud outgrowth, which affects tillering and grain yields of rice. However, how different N concentrations affect axillary bud growth at the molecular and transcriptional levels remains unclear. Results: In this study, morphological changes in the axillary bud growth of rice seedlings under different N concentrations ranging from low to high levels were systematically observed. To investigate the expression of N-induced genes involved in axillary bud growth, we used RNA-seq technology to generate mRNA transcriptomic data from two tissue types, basal parts and axillary buds, of plants grown under six different N concentrations. In total, 10,221 and 12,180 DEGs induced by LN or HN supplies were identified in the basal parts and axillary buds, respectively, via comparisons to expression levels under NN level. Analysis of the coexpression modules from the DEGs of the basal parts and axillary buds revealed an abundance of related biological processes underlying the axillary bud growth of plants under N treatments. Among these processes, the activity of cell division and expansion was positively correlated with the growth rate of axillary buds of plants grown under different N supplies. Additionally, TFs and phytohormones were shown to play crucial roles in determining the axillary bud growth of plants grown under different N concentrations. Further validation of OsGS1;2 and OsGS2 , the rice mutants of which presented altered tiller numbers, validated our transcriptomic data. Conclusion: These results indicate that different N concentrations affect the axillary bud growth rate, and our study revealed comprehensive expression profiles of genes that respond to different N concentrations, providing an important resource for future studies attempting to determine how axillary bud growth is controlled by different N supplies.


2019 ◽  
Author(s):  
Rongna Wang ◽  
Junjie Qian ◽  
Zhongming Fang ◽  
Jihua Tang

Abstract Background: N is an important macronutrient required for plant development and significantly influences axillary bud outgrowth, which affects tillering and grain yields of rice. However, how different N concentrations affect axillary bud growth at the molecular and transcriptional levels remains unclear. Results: In this study, morphological changes in the axillary bud growth of rice seedlings under different N concentrations ranging from low to high levels were systematically observed. To investigate the expression of N-induced genes involved in axillary bud growth, we used RNA-seq technology to generate mRNA transcriptomic data from two tissue types, basal parts and axillary buds, of plants grown under six different N concentrations. In total, 10,221 and 12,180 DEGs induced by LN or HN supplies were identified in the basal parts and axillary buds, respectively, via comparisons to expression levels under NN level. Analysis of the coexpression modules from the DEGs of the basal parts and axillary buds revealed an abundance of related biological processes underlying the axillary bud growth of plants under N treatments. Among these processes, the activity of cell division and expansion was positively correlated with the growth rate of axillary buds of plants grown under different N supplies. Additionally, TFs and phytohormones were shown to play crucial roles in determining the axillary bud growth of plants grown under different N concentrations. Further validation of OsGS1;2 and OsGS2 , the rice mutants of which presented altered tiller numbers, validated our transcriptomic data. Conclusion: These results indicate that different N concentrations affect the axillary bud growth rate, and our study revealed comprehensive expression profiles of genes that respond to different N concentrations, providing an important resource for future studies attempting to determine how axillary bud growth is controlled by different N supplies.


Weed Science ◽  
1989 ◽  
Vol 37 (2) ◽  
pp. 187-195 ◽  
Author(s):  
Emilie E. Regnier ◽  
Edward W. Stoller

Common cocklebur, jimsonweed, and velvetleaf were grown with soybeans in the field to determine how soybean interference affects weed canopy architecture. Common cocklebur had more leaves within the soybean canopy than jimsonweed or velvetleaf. At the end of the season, common cocklebur leaf area was distributed evenly below and above the top of the soybean canopy, while nearly all the jimsonweed and velvetleaf leaf area was above the soybean canopy. Common cocklebur exhibited more shade tolerance than jimsonweed or velvetleaf by also maintaining leaves in the shade within the soybean canopy. Differences among these weeds in leaf distribution within the soybean canopy were not related to differences in abscission of the lower leaves but to a differential response of lower axillary buds to soybean shading. Growth from lower axillary buds in jimsonweed and velvetleaf was strongly inhibited by soybean interference, but interference had little effect on lower axillary bud growth in common cocklebur. Axillary bud growth in the lower canopies of both common cocklebur and soybeans, and their similarity in height, caused these plants to compete for the same aboveground niche. However, common cocklebur had more extensive axillary growth along the lower stem than soybeans, which may allow it to compete for resources in this niche more aggressively than soybeans. Velvetleaf and jimsonweed did not share the same aboveground niche with soybeans due to the placement of their leaves above rather than within the soybean canopy. The lower branching characteristics and apparent shade tolerance of common cocklebur may be important factors in the superior competitive ability with soybeans compared to jimsonweed and velvetleaf.


2020 ◽  
Author(s):  
Rongna Wang ◽  
Junjie Qian ◽  
Zhongming Fang ◽  
Jihua Tang

Abstract Background: N is an important macronutrient required for plant development and significantly influences axillary bud outgrowth, which affects tillering and grain yields of rice. However, how different N concentrations affect axillary bud growth at the molecular and transcriptional levels remains unclear. Results: In this study, morphological changes in the axillary bud growth of rice seedlings under different N concentrations ranging from low to high levels were systematically observed. To investigate the expression of N-induced genes involved in axillary bud growth, we used RNA-seq technology to generate mRNA transcriptomic data from two tissue types, basal parts and axillary buds, of plants grown under six different N concentrations. In total, 10,221 and 12,180 DEGs induced by LN or HN supplies were identified in the basal parts and axillary buds, respectively, via comparisons to expression levels under NN level. Analysis of the coexpression modules from the DEGs of the basal parts and axillary buds revealed an abundance of related biological processes underlying the axillary bud growth of plants under N treatments. Among these processes, the activity of cell division and expansion was positively correlated with the growth rate of axillary buds of plants grown under different N supplies. Additionally, TFs and phytohormones were shown to play crucial roles in determining the axillary bud growth of plants grown under different N concentrations. Further validation of OsGS1;2 and OsGS2 , the rice mutants of which presented altered tiller numbers, validated our transcriptomic data. Conclusion: These results indicate that different N concentrations affect the axillary bud growth rate, and our study revealed comprehensive expression profiles of genes that respond to different N concentrations, providing an important resource for future studies attempting to determine how axillary bud growth is controlled by different N supplies.


Agronomy ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 594
Author(s):  
Yali Li ◽  
Jiangtao Hu ◽  
Jie Xiao ◽  
Ge Guo ◽  
Byoung Ryong Jeong

Strawberry (Fragaria × ananassa Duch.) can be easily propagated with daughter plants or through crown division, which are developed from the axillary bud at the axils of leaves. This study was conducted to investigate the effects of different cytokinins, auxins, and their combinations on the axillary bud growth in strawberry. Four cytokinins (6-benzyladenine, kinetin, zeatin, and thidiazuron (TDZ)) and three auxins (indole-3-acetic acid, indole-3-butyric acid, and naphthaleneacetic acid) at a concentration of 50 mg·L−1 were sprayed on the leaves three times in 10-day intervals. The expression levels of cytokinin, auxin, and meristem-related genes in the crowns were also investigated. The results showed that TDZ was the most effective hormone for the axillary bud growth, and also promoted plant growth. However, chlorophyll, soluble sugar, and starch contents in the leaves were lower after TDZ. TDZ activated the cytokinin signal transduction pathway, while repressing the auxin synthesis genes. Several meristem-related transcription factors were upregulated, which might be essential for the growth of the axillary buds. These results suggested that TDZ can improve the cultivation of strawberry, while further research is needed to explain the effect on phytochemistry.


2021 ◽  
Vol 13 (2) ◽  
pp. 11
Author(s):  
Yunzhou Li ◽  
Ningbo Yue ◽  
Abdul Basit ◽  
Yulong Li ◽  
Dalong Zhang ◽  
...  

The mitogen-activated protein kinase (MAPK) cascade signaling system has been relatively conserved throughout the evolution of eukaryotes and is involved in the regulation of growth and development and metabolism. In this study, dwarf tomato plants were used as the research material. First, the tissue-specific expression of SlMAPK6 was measured in wild-type plants by quantitative RT-PCR. The results showed that SlMAPK6 was highly expressed in the tissues of the stems, leaves and flowers but was expressed at low levels in the tissues of the roots, sepals and fruits. Second, SlMAPK6-knockout lines CRISPR-3 and CRISPR-7 were obtained by CRISPR-Cas9 technology and Agrobacterium-mediated transformation. Compared with wild-type, the mutant lines CRISPR-3 and CRISPR-7 showed significant phenotypic characteristics, such as increased numbers of axillary buds and true leaves, thickened stems, and longer leaflets. In addition, to explore the molecular mechanism by which MAPK regulates axillary bud growth, we also showed that SlMAPK6 positively regulates the strigolactone synthesis genes SlCCD7 and SlCCD8 and the gibberellin (GA) synthesis genes GA20ox3 and GA3ox1 and negatively regulates the axillary bud development-related genes Ls, BL and BRC1b/TCP8 and the GA synthesis inhibitory gene GAI. Therefore, SlMAPK6 appears to regulate the synthesis of strigolactone and GA to induce the growth and development of tomato axillary buds.


2020 ◽  
Author(s):  
Rongna Wang ◽  
Junjie Qian ◽  
Zhongming Fang ◽  
Jihua Tang

Abstract Background: N is an important macronutrient required for plant development and significantly influences axillary bud outgrowth, which affects tillering and grain yields of rice. However, how different N concentrations affect axillary bud growth at the molecular and transcriptional levels remains unclear. Results: In this study, morphological changes in the axillary bud growth of rice seedlings under different N concentrations ranging from low to high levels were systematically observed. To investigate the expression of N-induced genes involved in axillary bud growth, we used RNA-seq technology to generate mRNA transcriptomic data from two tissue types, basal parts and axillary buds, of plants grown under six different N concentrations. In total, 10,221 and 12,180 DEGs induced by LN or HN supplies were identified in the basal parts and axillary buds, respectively, via comparisons to expression levels under NN level. Analysis of the coexpression modules from the DEGs of the basal parts and axillary buds revealed an abundance of related biological processes underlying the axillary bud growth of plants under N treatments. Among these processes, the activity of cell division and expansion was positively correlated with the growth rate of axillary buds of plants grown under different N supplies. Additionally, TFs and phytohormones were shown to play crucial roles in determining the axillary bud growth of plants grown under different N concentrations. Further validation of OsGS1;2 and OsGS2 , the rice mutants of which presented altered tiller numbers, validated our transcriptomic data. Conclusion: These results indicate that different N concentrations affect the axillary bud growth rate, and our study revealed comprehensive expression profiles of genes that respond to different N concentrations, providing an important resource for future studies attempting to determine how axillary bud growth is controlled by different N supplies.


2012 ◽  
Vol 5 (2) ◽  
pp. 173-182 ◽  
Author(s):  
Brian P. O’Neill ◽  
Matthew P. Purnell ◽  
David J. Anderson ◽  
Lars K. Nielsen ◽  
Stevens M. Brumbley

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