May 2015, Volume 57 Issue 5, Pages 450每514.


Cover Caption: Double Fertilization in Arabidopsis
The pollen tube of flowering plants delivers two sperms to the embryo sac for double fertilization. In this issue, Huang et al. (pp. 496每503) discovered dynamic changes of these gametes within the embryo sac, and found that successful double fertilization requires a one-step modification of sperm cell targeting, suggesting multiple information flows among gamete cells.

 

          Cell and Developmental Biology
Constructing a high-density linkage map for Gossypium hirsutum ℅ Gossypium barbadense and identifying QTLs for lint percentage
Author: Yuzhen Shi, Wentan Li, Aiguo Li, Ruihua Ge, Baocai Zhang, Junzhi Li, Guangping Liu, Junwen Li, Aiying Liu, Haihong Shang, Juwu Gong, Wankui Gong, Zemao Yang, Feiyü Tang, Zhi Liu, Weiping Zhu, Jianxiong Jiang, Xiaonan Yu, Tao Wang, Wei Wang, Tingting Chen, Kunbo Wang, Zhengsheng Zhang and Youlu Yuan
Journal of Integrative Plant Biology 2015 57(5): 450每467
Published Online: September 27, 2014
DOI: 10.1111/jipb.12288
      
    
To introgress the good fiber quality and yield from Gossypium barbadense into a commercial Upland cotton variety, a high-density simple sequence repeat (SSR) genetic linkage map was developed from a BC1F1 population of Gossypium hirsutum × Gossypium barbadense. The map comprised 2,292 loci and covered 5115.16 centiMorgan (cM) of the cotton AD genome, with an average marker interval of 2.23 cM. Of the marker order for 1,577 common loci on this new map, 90.36% agrees well with the marker order on the D genome sequence genetic map. Compared with five published high-density SSR genetic maps, 53.14% of marker loci were newly discovered in this map. Twenty-six quantitative trait loci (QTLs) for lint percentage (LP) were identified on nine chromosomes. Nine stable or common QTLs could be used for marker-assisted selection. Fifty percent of the QTLs were from G. barbadense and increased LP by 1.07%–2.41%. These results indicated that the map could be used for screening chromosome substitution segments from G. barbadense in the Upland cotton background, identifying QTLs or genes from G. barbadense, and further developing the gene pyramiding effect for improving fiber yield and quality.

 

Shi Y, Li W, Li A, Ge R, Zhang B, Li J, Liu G, Li J, Liu A, Shang H, Gong J, Gong W, Yang Z, Tang F, Liu Z, Zhu W, Jiang J, Yu X, Wang T, Wang W, Chen T, Wang K, Zhang Z, Yuan Y (2015) Constructing a high坼density linkage map for Gossypium hirsutum × Gossypium barbadense and identifying QTLs for lint percentage. J Integr Plant Biol 57: 450–467. doi: 10.1111/jipb.12288

Abstract (Browse 1256)  |  References  |  Full Text HTML  |  Full Text PDF  |  Cited By       
Upland cotton has high yield and Island cotton has superior fiber properties. To introgress the good fiber quality from Island cotton into an Upland cotton variety, a high-density genetic linkage map, with 2,292 loci and covered 5,115.16cM of the cotton genome, was developed from an interspecific population.
          Molecular Physiology
Regulation of pepc gene expression in Anabaena sp. PCC 7120 and its effects on cyclic electron flow around photosystem I and tolerances to environmental stresses
Author: Xiao-Hui Jia, Peng-Peng Zhang, Ding-Ji Shi, Hua-Ling Mi, Jia-Cheng Zhu, Xi-Wen Huang and Pei-Min He
Journal of Integrative Plant Biology 2015 57(5): 468每476
Published Online: July 8, 2014
DOI: 10.1111/jipb.12241
      
    

Since pepc gene encoding phosphoenolpyruvate carboxylase (PEPCase) has been cloned from Anabaena sp. PCC 7120 and other cyanobacteria, the effects of pepc gene expression on photosynthesis have not been reported yet. In this study, we constructed mutants containing either upregulated (forward) or downregulated (reverse) pepc gene in Anabaena sp. PCC 7120. Results from real-time quantitative polymerase chain reaction (RT-qPCR), Western blot and enzymatic analysis showed that PEPCase activity was significantly reduced in the reverse mutant compared with the wild type, and that of the forward mutant was obviously increased. Interestingly, the net photosynthesis in both the reverse mutant and the forward mutant were higher than that of the wild type, but dark respiration was decreased only in the reverse mutant. The absorbance changes of P700 upon saturation pulse showed the photosystem I (PSI) activity was inhibited, as reflected by Y(I), and Y(NA) was elevated, and dark reduction of P700+ was stimulated, indicating enhanced cyclic electron flow (CEF) around PSI in the reverse mutant. Additionally, the reverse mutant photosynthesis was higher than that of the wild type in low temperature, low and high pH, and high salinity, and this implies increased tolerance in the reverse mutant through downregulated pepc gene.

 

 

Jia XH, Zhang PP, Shi DJ, Mi HL, Zhu JC, Huang XW, He PM (2015) Regulation of pepc gene expression in Anabaena sp. PCC 7120 and its effects on cyclic electron flow around photosystem I and tolerances to environmental stresses. J Integr Plant Biol 57: 468–476. doi: 10.1111/jipb.12241

Abstract (Browse 991)  |  References  |  Full Text HTML  |  Full Text PDF  |  Cited By       
The effects of pepc gene expression on Cyanobacteria photosynthesis have not been reported. This study found that PSI activity of Anabaena was inhibited and dark reduction of P700+ was stimulated in reverse mutant (down-regulated pepc), indicating enhanced cyclic electron flow around PSI and increased tolerances of temperature, pH and salinity .
Effects of transgenic soybean on growth and phosphorus acquisition in mixed culture system  
Author: Jianna Xie, Jia Zhou, Xiurong Wang and Hong Liao
Journal of Integrative Plant Biology 2015 57(5): 477每485
Published Online: July 21, 2014
DOI: 10.1111/jipb.12243
      
    

Transgenic soybean plants overexpressing the Arabidopsis purple acid phosphatase gene AtPAP15 (OXp) or the soybean expansin gene GmEXPB2 (OXe) can improve phosphorous (P) efficiency in pure culture by increasing Apase secretion or changing root morphology. In this study, soybean-soybean mixed cultures were employed to illuminate P acquisition among plants in mixed stands of transgenic and wild-type soybean. Our results showed that transgenic soybean plants were much more competitive, and had greater growth and P uptake than wild-type soybean in mixed culture in both low P calcareous and acid soils. Furthermore, OXe plants had an advantage in calcareous soils when mixed with OXp, whereas the latter performed much better in acid soils. In soybean-maize mixed culture, transgenic soybean had no impact on maize growth compared to controls in both acid and calcareous soils with different P conditions. As for soybean in mixed culture, OXp plants had no significant advantages regardless of P availability or soil type, while P efficiency improved in OXe in calcareous soils compared to controls. These results imply that physiological traits could be easily affected by the mixed maize. Transgenic soybean plants with enhanced root traits had more competitive advantages than those with improved root physiology in mixed culture.

 

Xie J, Zhou J, Wang X, Liao H (2015) Effects of transgenic soybean on growth and phosphorus acquisition in mixed culture system. J Integr Plant Biol 57: 477–485. doi: 10.1111/jipb.12243

Abstract (Browse 854)  |  References  |  Full Text HTML  |  Full Text PDF  |  Cited By       
In soybean-soybean mixed culture, transgenic soybean plants were much more competitive. In soybean-maize culture, transgenic soybean had no impact on maize growth, whereas soybean physiological traits could be easily affected by the mixed maize. Therefore, genetic modification of root traits might be a more suitable strategy for improving crop production.
Calcium contributes to photoprotection and repair of photosystem II in peanut leaves during heat and high irradiance  
Author: Sha Yang, Fang Wang, Feng Guo, Jing-Jing Meng, Xin-Guo Li and Shu-Bo Wan
Journal of Integrative Plant Biology 2015 57(5): 486每495
Published Online: August 7, 2014
DOI: 10.1111/jipb.12249
      
    

In this study, we investigated the effects of exogenous calcium nitrate on photoinhibition and thylakoid protein level in peanut plants under heat (40 °C) and high irradiance (HI) (1,200 µmol/m2 per s) stress. Compared with control seedlings (cultivated in 0 mmol/L Ca(NO3)2 medium), the maximal photochemical efficiency of photosystem II (PSII) in Ca2+-treated plants showed a slight decrease after 5 h stress, accompanied by lower degree of PSII closure (1-qP), higher non-photochemical quenching, and lower level of membrane damage. Ca2+ inhibitors were used to analyze the varieties of antioxidant enzymes activity and PSII proteins. These results indicated that Ca2+ could protect the subunits of PSII reaction centers from photoinhibition by reducing the generation of reactive oxygen species. In the presence of both ethyleneglycol-bis(2-aminoethylether)-tetraacetic acid and ascorbic acid (AsA), the net degradation of the damaged D1 protein was faster than that only treated with AsA. Our previous study showed that either the transcriptional or the translational level of calmodulin was obviously higher in Ca2+-treated plants. These results suggested that, under heat and HI stress, the Ca2+ signal transduction pathway can alleviate the photoinhibition through regulating the protein repair process besides an enhanced capacity for scavenging reactive oxygen species.

 

Yang S, Wang F, Guo F, Meng JJ, Li XG, Wan SB (2015) Calcium contributes to photoprotection and repair of photosystem II in peanut leaves during heat and high irradiance. J Integr Plant Biol 57: 486–495 doi: 10.1111/jipb.12249

Abstract (Browse 1025)  |  References  |  Full Text HTML  |  Full Text PDF  |  Cited By       
This work shows that exogenous Ca2+ could help to protect the peanut photosynthetic apparatus from severe photoinhibition under heat and HI stress by accelerating the repair of Photosystem II center proteins.
          Plant Reproduction Biology
A one-step rectification of sperm cell targeting ensures the success of double fertilization
Author: Jilei Huang, Yan Ju, Xiangfeng Wang, Quan Zhang and Sodmergen
Journal of Integrative Plant Biology 2015 57(5): 496每503
Published Online: December 22, 2014
DOI: 10.1111/jipb.12322
      
    

Successful fertilization in animals depends on competition among millions of sperm cells, whereas double fertilization in flowering plants usually involves just one pollen tube releasing two immobile sperm cells. It is largely a mystery how the plant sperm cells fuse efficiently with their female targets within an embryo sac. We show that the initial positioning of sperm cells upon discharge from the pollen tube is usually inopportune for gamete fusions and that adjustment of sperm cell targeting occurs through release and re-adhesion of one sperm cell, while the other connected sperm cell remains in stagnation. This enables proper adhesion of each sperm cell to a female gamete and coordinates the gamete fusions. Our findings reveal inner embryo sac dynamics that ensure the reproductive success of flowering plants and suggest a requirement for sperm cell differentiation as the basis of double fertilization.

 

Huang J, Ju Y, Wang X, Zhang Q, Sodmergen (2015) A one-step rectification of sperm cell targeting ensures the success of double fertilization. J Integr Plant Biol 57: 496–503 doi: 10.1111/jipb.12322

Abstract (Browse 793)  |  References  |  Full Text HTML  |  Full Text PDF  |  Cited By       
It is largely a mystery that how immobile sperm cells of flowering plants get into fusions with the egg and central cells. Through live-cell imaging of the embryo sac, we show a dramatic release and re-adhesion of one sperm cell, modifying gamete associations and ensuring the success of double fertilization.
OsMADS32 interacts with PI-like proteins and regulates rice flower development  
Author: Huanhuan Wang, Liang Zhang, Qiang Cai, Yun Hu, Zhenming Jin, Xiangxiang Zhao, Wei Fan, Qianming Huang, Zhijing Luo, Mingjiao Chen, Dabing Zhang and Zheng Yuan
Journal of Integrative Plant Biology 2015 57(5): 504每513
Published Online: August 1, 2014
DOI: 10.1111/jipb.12248
      
    

OsMADS32 is a monocot specific MIKCc type MADS-box gene that plays an important role in regulating rice floral meristem and organs identity, a crucial process for reproductive success and rice yield. However, its underlying mechanism of action remains to be clarified. Here, we characterized a hypomorphic mutant allele of OsMADS32/CFO1, cfo1-3 and identified its function in controlling rice flower development by bioinformatics and protein-protein interaction analysis. The cfo1-3 mutant produces defective flowers, including loss of lodicule identity, formation of ectopic lodicule or hull-like organs and decreased stamen number, mimicking phenotypes related to the mutation of B class genes. Molecular characterization indicated that mis-splicing of OsMADS32 transcripts in the cfo1-3 mutant resulted in an extra eight amino acids in the K-domain of OsMADS32 protein. By yeast two hybrid and bimolecular fluorescence complementation assays, we revealed that the insertion of eight amino acids or deletion of the internal region in the K1 subdomain of OsMADS32 affects the interaction between OsMADS32 with PISTILLATA (PI)-like proteins OsMADS2 and OsMADS4. This work provides new insight into the mechanism by which OsMADS32 regulates rice lodicule and stamen identity, by interaction with two PI-like proteins via its K domain.

 

Wang H, Zhang L, Cai Q, Hu Y, Jin Z, Zhao X, Fan W, Huang Q, Luo Z, Chen M, Zhang D, Yuan Z (2015) OsMADS32 interacts with PI坼like proteins and regulates rice flower development. J Integr Plant Biol 57:
504–513. doi: 10.1111/jipb.12248

Abstract (Browse 1222)  |  References  |  Full Text HTML  |  Full Text PDF  |  Cited By       
Rice spikelet has a distinct morphology, and its development determines rice grain yield. In this study, we showed that a monocot-specific MADS-box protein, OsMADS32 may interact with PI-like proteins OsMADS2 and OsMADS4 via its K domain in specifying lodicules and stamens development.
 

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