In situ detection of salicylic acid binding sites in plant tissues.
The determination of hormone-binding sites in plants is essential in understanding the mechanisms behind hormone function. Salicylic acid (SA) is an important plant hormone that regulates responses to biotic and abiotic stresses. In order to label SA-binding sites in plant tissues, a quantum dots (QDs) probe functionalized with a SA moiety was successfully synthesized by coupling CdSe QDs capped with 3-mercaptopropionic acid (MPA) to 4-amino-2-hydroxybenzoic acid (PAS), using 1-ethyl-3-(3-dimethyllaminopropyl) carbodiimide (EDC) as the coupling agent. The probe was then characterized by dynamic light scattering and transmission electron microscopy, as well as UV/vis and fluorescence spectrophotometry. The results confirmed the successful conjugation of PAS to CdSe QDs and revealed that the conjugates maintained the properties of the original QDs, with small core diameters and adequate dispersal in solution. The PAS-CdSe QDs were used to detect SA-binding sites in mung bean and Arabidopsis thaliana seedlings in vitro and in vivo. The PAS-CdSe QDs were effectively transported into plant tissues and specifically bound to SA receptors in vivo. In addition, the effects of the PAS-CdSe QDs on cytosolic Ca(2+) levels in the tips of A. thaliana seedlings were investigated. Both SA and PAS-CdSe QDs had similar effects on the trend in cytosolic-free Ca(2+) concentrations, suggesting that the PAS-CdSe QDs maintained the bioactivity of SA. To summarize, PAS-CdSe QDs have high potential as a fluorescent probe for the in vitro/in vivo labeling and imaging of SA receptors in plants.
School of Chemistry and Environment, South China Normal University, Guangzhou, Guangdong, 510006, People's Republic of China.
Jing-Wen
JW
Liu
Da-Yi
DY
Deng
Ying
Y
Yu
Fang-Fei
FF
Liu
Bi-Xia
BX
Lin
Yu-Juan
YJ
Cao
Xiao-Gang
XG
Hu
Jian-Zhong
JZ
Wu
D017360:Arabidopsis / Q000737:chemistry*; D001665:Binding Sites; D019187:Cadmium Compounds / Q000138:chemical synthesis / Q000737:chemistry* / Q000302:isolation & purification; D010316:Particle Size; D045663:Quantum Dots; D020156:Salicylic Acid / Q000032:analysis*; D012639:Seeds / Q000737:chemistry*; D018036:Selenium Compounds / Q000138:chemical synthesis / Q000737:chemistry* / Q000302:isolation & purification; D013499:Surface Properties
D019187:Cadmium Compounds; D018036:Selenium Compounds; C058667:cadmium selenide; D020156:Salicylic Acid
CdSe; bind site; in situ; labeling; salicylic acid