Spontaneous nodules induce feedback suppression of nodulation in alfalfa

Planta ◽  
1991 ◽  
Vol 183 (1) ◽  
Author(s):  
Gustavo Caetano-Anoll�s ◽  
PriyavadanA. Joshi ◽  
PeterM. Gresshoff
Keyword(s):  
Feedback Suppression ◽  
Spontaneous Nodules

scholarly journals Phytosulfokine Is Involved in Positive Regulation of Lotus japonicus Nodulation

2015 ◽  
Vol 28 (8) ◽  
pp. 847-855 ◽  
Author(s):  
Chao Wang ◽  
Haixiang Yu ◽  
Zhongming Zhang ◽  
Liangliang Yu ◽  
Xiaoshu Xu ◽  
...  
Keyword(s):  
Potential Role ◽  
Early Stage ◽  
Root Nodules ◽  
Lotus Japonicus ◽  
Positive Regulation ◽  
Transgenic Hairy Roots ◽  
Exogenous Addition ◽  
Nodule Initiation ◽  
Spontaneous Nodules

Phytosulfokine (PSK) is a tyrosine-sulfated peptide that is widely distributed in plants, participating in cell proliferation, differentiation, and innate immunity. The potential role of PSK in nodulation in legumes has not been reported. In this work, five PSK precursor genes were identified in Lotus japonicas, designated as LjPSK1 to LjPSK5. Three of them (LjPSK1, LjPSK4, and LjPSK5) were found to be expressed in nitrogen-fixing root nodules. LjPSK1 and LjPSK4 were not induced at the early stage of nodulation. Interestingly, while the expression of LjPSK4 was also found in spontaneous nodules without rhizobial colonization, LjPSK1 was not induced in these pseudo nodules. Promoter-β-glucuronidase analysis revealed that LjPSK1 was highly expressed in enlarged symbiotic cells of nodules. Exogenous addition of 1 μM synthetic PSK peptide resulted in increased nodule numbers per plant. Consistently, the number of mature nodules but not the events of rhizobial infection and nodule initiation was increased by overexpressing LjPSK1 in transgenic hairy roots, in which the expression of jasmonate-responsive genes was found to be repressed. These results suggest that PSK is a new peptide signal that regulates nodulation in legumes, probably through cross-talking with other phytohormones.

Gain properties and optical-feedback suppression of asymmetrical curved active waveguides

2009 ◽  
Vol 2 (4) ◽  
pp. 379-383
Author(s):  
Zigang Duan ◽  
Wei Shi ◽  
Yan Li ◽  
Guangyue Chai
Keyword(s):  
Optical Feedback ◽  
Feedback Suppression
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