br Results and discussion br Conclusion In

Results and discussion
Conclusion In conclusion, our present results indicated that l-glutamate treatment could induce resistant to B. cinerea in postharvest tomatoes. The control effect was probably associated with up-regulating the glutamate receptor-like genes, PR genes and the accumulation of Sotalol in tomato fruit. It was suggested that application of l-glutamate may be a promising alternative approach to partly substitute synthetic fungicides to control decay of tomatoes. The possible modes of action by which l-glutamate induced resistance to B. cinerea in postharvest tomatoes, is shown in Fig. S2. Nonetheless, further studies need to be conducted to study the l-glutamate treatment on disease resistance against other postharvest fungal pathogens and the comprehensive mechanisms with the pathogen challenge in tomato fruit.
Declaration of interests
Acknowledgements This research was supported by the National key R & D program (2016YFD0401201) and the National Natural Science Foundation of China (31471627).
Introduction Signal processing in the retina is controlled by the integration of excitatory and inhibitory inputs of retinal neurons (Kaneda, 2013; Wassle, 2004). Photoreceptors and bipolar cells are glutamatergic, and a signaling pathway from photoreceptors to ganglion cells is formed via bipolar cells (Fig. 2A). Glutamatergic signals also drive neurotransmitter release from horizontal cells and amacrine cells. Horizontal cells and amacrine cells are principally GABAergic or glycinergic and form neural feedback circuits. Due to the importance of glutamatergic circuits for signal processing in the mammalian retina, glutamatergic signaling mechanisms have been an attractive target for study. The distribution of glutamate receptor “subtype” of retinal neurons has been characterized by immunohistochemical techniques (Brandstatter et al., 1996; Brandstatter et al., 1998; Dumitrescu et al., 2006; Ghosh et al., 2001; Koulen et al., 1997, Koulen et al., 1996; Yang and Yazulla, 1994). The response properties of each glutamate receptor “subtype” have been characterized by electrophysiological methods in horizontal cells (Tachibana, 1983), bipolar cells (de la Villa et al., 1995; Euler et al., 1996; Ishida et al., 1984; Sasaki and Kaneko, 1996; Tachibana and Kaneko, 1988; Tagawa et al., 1999; Yamashita and Wassle, 1991), amacrine cells (Ishii and Kaneda, 2014), and ganglion cells (Matsui et al., 1998). Studies of glutamate “release from the axon terminals”(Kobayashi et al., 1995; Logiudice et al., 2009; Mennerick and Matthews, 1996; Sakaba et al., 1997; Tachibana and Okada, 1991; von Gersdorff et al., 1998; von Gersdorff et al., 1996) and “the imaging technique” (Midorikawa et al., 2007) have revealed the Ca-dependence and spatial-temporal profile of glutamate release at the single cell level. The difference in the time course of glutamate release among individual subtypes of bipolar cells in the mammalian retina might be important for parallel processing of visual information (Franke et al., 2017; Ichinose et al., 2014; Ichinose and Hellmer, 2016) and the formation of direction selectivity (Greene et al., 2016; Kim et al., 2014). In addition, the development of an intensity-based glutamate-sensing fluorescent reporter (iGluSnFR) has enabled monitoring of the glutamate concentration at the synaptic cleft in many neural systems including the retina (Borghuis et al., 2013; Marvin et al., 2013). Recently, a newly designed enzyme-linked fluorescence assay system has enabled monitoring of GABA dynamics at the laminar level in the cerebrum and cerebellum in slice preparations (Morishima et al., 2010; Wang et al., 2014). In the retina, although measurement of glutamate release by the enzyme-linked fluorescence assay system has been reported at the single cell level (Ayoub and Copenhagen, 1991), there have been no reports monitoring glutamate dynamics at the laminar level. To further understand how the glutamatergic circuit works in the retina, we applied an enzyme-linked fluorescence assay system to monitor glutamate dynamics at the laminar level in the mouse retina. We found that our system was a useful tool to monitor glutamate dynamics in the retina at the laminar level, especially in the inner retina.