GLUTAMATE RECEPTOR-LIKE genes mediate leaf-to-leaf wound signalling

Abstract

Unlike plants, animals rely on rapid nervous systems to escape predation. A stationary fly that perceives danger takes less than 300 ms to take off, and this process requires complex whole- to ion fluxes in cell populations in wounded Arabidopsis plants. As summarised in Supplementary Fig. 1, we show that electrical signalling activates jasmonate biosynthesis in leaves distal to wounds and we identify genes involved in electrical signal propagation. Wound-induced surface potential changesTo investigate patterns of electrical activity and gene expression in 5 week-old rosettes, individual leaves were numbered from oldest to youngest. Electrodes placed on leaf 8 at the midrib/petiole junction (e2 electrode position) and on the petiole (position e3) did not detect changes in electrical activity and such changes were not elicited by walking S. littoralis larvae (Fig. 1b). When recordings were extended, they often showed periodicity ( Supplementary Fig. 3). We used three parameters to characterise these signals: latency (time from wounding to arrival at the amplitude midpoint), amplitude and duration (Fig. 1b). To gain more information on the spread of WASPs within a wounded leaf, four electrodes were placed on the leaf surface (Fig. 1a). After damage, WASPs were detected first at e1, then several seconds later at e2, and finally at e3. An electrode on the lamina also detected damage-elicited electrical activity and, in each case (Fig. 1c), the changes in amplitude were typically close to -70 mV (SupplementaryTable 1). The signals we measured had the same polarity as those produced after a chilling treatment known to cause plasma membrane depolarisation 24,25 . Therefore WASPs in leaf 8 were due to plasma membrane depolarisation ( Supplementary Fig. 4). The WASPs detected on WT plants were indistinguishable to those on wounded plants that lacked the ability to synthesize jasmonates ( Supplementary Fig. 5).This suggests that the mechanism that produces WASPs is upstream or independent of jasmonate synthesis. WASP territories and speedsSignals generated by wounding leaf tips first move towards the centre of the rosette and then disperse away from the apex into a restricted number of distal leaves to initiate distal JA accumulation and signalling 11 . In order to map the spatial distribution of WASPs in the rosette after wounding leaf 8 we placed electrodes in the e3 position of leaves 5 through 18. Leaves 5, 11, 13 and 16 showed responses similar to those in the wounded leaf (Fig. 1d, Supplementary Table 2). For example, after wounding leaf 8, a WASP with a duration of 78±20 s and a peak amplitude of -51 ± 9 mV was reached in leaf 13 after a latency of 66 ± 13 s (n=61 plants). Other leaves (7, 9, 10, 12, 14, 15,17 and 18) showed small positive surface potential changes. For example, leaf 9 showed a 20±5 mV change in surface potential with a latency of 54±12 s (n=46 plants). Most of these observations fit a developmental pattern: In adult-phase Arabidopsis rosettes, leaf 'n' shares direct vascular connections to leave...

Interaction between MYC2 and ETHYLENE INSENSITIVE3 Modulates Antagonism between Jasmonate and Ethylene Signaling inArabidopsis

“…Upon perception of JA signal (Fonseca et al, 2009;Yan et al, 2009;Sheard et al, 2010), the F-box protein CORO-NATINE INSENSITIVE1 (COI1) (Xie et al, 1998;Yan et al, 2009) recruits the JASMONATE ZIM-DOMAIN (JAZ) proteins (Chini et al, 2007;Thines et al, 2007;Yan et al, 2007) for degradation, which leads to the release of various downstream factors, including MYC2/JASMONATE INSENSITIVE1 (JIN1), MYC3, and MYC4 (Cheng et al, 2011;Fernández-Calvo et al, 2011;Niu et al, 2011), as well as WD-repeat/bHLH/MYB complex , MYB21, MYB24, and MYB57 (Mandaokar et al, 2006;Song et al, 2011) and the IIId bHLH factors (Nakata et al, 2013;Song et al, 2013b), which regulate diverse JA-mediated functions. These functions include root growth (Dathe et al, 1981;Chen et al, 2011), apical hook formation (Turner et al, 2002), flowering (Robson et al, 2010), stamen development (McConn and Browse, 1996;Song et al, 2011Song et al, , 2013a, leaf senescence (Ueda and Kato, 1980;Shan et al, 2011), secondary metabolism (De Geyter et al, 2012;Schweizer et al, 2013), drought responses (Seo et al, 2011), wounding responses (Mason and Mullet, 1990;Acosta et al, 2013;Mousavi et al, 2013), and defense against pathogen infection Vijayan et al, 1998;Melotto et al, 2006;Rowe et al, 2010;Yang et al, 2012;Zheng et al, 2012) and insect attack (McConn et al, 1997;…”

WIND1 Promotes Shoot Regeneration through Transcriptional Activation of ENHANCER OF SHOOT REGENERATION1 in Arabidopsis

“…Wounding provokes various physiological responses, including rapid induction of reactive oxygen species, Ca 2+ waves, and the production of stress-responsive hormones (Miller et al, 2009;Mousavi et al, 2013), but whether these early physiological responses direct cells for reprogramming is not established. A set of key regulators that are rapidly activated in response to wounding and have pivotal roles in wound-induced callus formation are a subfamily of AP2/ERF transcription factors, WOUND INDUCED DEDIFFERENTIATION1 (WIND1; aka RAP2.4), WIND2, WIND3, and WIND4 (Iwase et al, 2011a(Iwase et al, , 2011b.…”

Variation potential in higher plants: Mechanisms of generation and propagation

“…15 Propagation of AP and VP affects numerous physiological processes in plants. For example, ESs induce gene expression, [16][17][18] phytohormone synthesis, 17,19,20 phloem transport decrease, 21 changes in root absorption, 11 activation of respiration, [22][23][24][25][26] and inactivation of photosynthesis. 23,24,[26][27][28][29][30][31] Retivin et al 32 hypothesized that the ultimate role of these physiological changes is the increase of plant resistance to stressors.…”