Ethylene Signaling Influences Light-Regulated Development in Pea

Abstract

Plant responses to light involve a complex network of interactions among multiple plant hormones. In a screen for mutants showing altered photomorphogenesis under red light, we identified a mutant with dramatically enhanced leaf expansion and delayed petal senescence. We show that this mutant exhibits reduced sensitivity to ethylene and carries a nonsense mutation in the single pea (Pisum sativum) ortholog of the ethylene signaling gene ETHYLENE INSENSITIVE2 (EIN2). Consistent with this observation, the ein2 mutation rescues the previously described effects of ethylene overproduction in mature phytochromedeficient plants. In seedlings, ein2 confers a marked increase in leaf expansion under monochromatic red, far-red, or blue light, and interaction with phytochromeA, phytochromeB, and long1 mutants confirms that ein2 enhances both phytochrome-and cryptochrome-dependent responses in a LONG1-dependent manner. In contrast, minimal effects of ein2 on seedling development in darkness or high-irradiance white light show that ethylene is not limiting for development under these conditions. These results indicate that ethylene signaling constrains leaf expansion during deetiolation in pea and provide further evidence that down-regulation of ethylene production may be an important component mechanism in the broader control of photomorphogenic development by phytochrome and cryptochrome.

Nitric Oxide, Ethylene, and Auxin Cross Talk Mediates Greening and Plastid Development in Deetiolating Tomato Seedlings

“…Treatments with ethylene biosynthesis inhibitor or mutation in the ethylene signaling gene ETHYLENE INSENSITIVE2 rescued many of the phenotype alterations observed in this pea mutant (Foo et al, 2006;Weller et al, 2015). Therefore, light perception via phytochromes is believed to play a critical role in reducing ethylene synthesis to levels compatible with the induction and progression of key photomorphogenic responses (Vangronsveld et al, 1988;Foo et al, 2006;Weller et al, 2015).…”

“…Given the importance of ethylene during plant responses to light (Rodrigues et al, 2014;Van de Poel et al, 2015;Weller et al, 2015) and its close interplay with NO during diverse plant responses (Manjunatha et al, 2012;Freschi, 2013), we next analyzed whether NO-ethylene interactions regulate tomato seedling greening and chloroplast development.…”

Focus on Ethylene

“…In the 2004 issue, two articles focused on specific downstream ethylene responses of shade avoidance and hyponastic growth. This issue features studies on aerenchyma formation (Yamauchi et al, 2015), root growth (Street et al, 2015), hypocotyl growth (Sun et al, 2015), hyponastic growth (Polko et al, 2015), abscission (Eccher et al, 2015), leaf senescence (Ueda and Kusaba, 2015), and the interaction of ethylene with light to regulate development (Weller et al, 2015). Of note, three articles in this issue emphasize a previously unheralded role for ethylene as an inhibitor of cell proliferation in both the shoot and root of Arabidopsis (Polko et al, 2015;Street et al, 2015;Tao et al, 2015).…”

Struggle to survive: aphid—plant relationships under low-light stress. A case of Acyrthosiphon pisum (Harris) and Pisum sativum L.

“…Apart from being the primary source of energy, light also plays signaling and regulatory roles in developmental processes thanks to photoreceptors that receive and transmit light signals (Gyula et al 2003;Chory 2010;Eckstein et al 2012). The developmental changes that occur in response to light exposure are associated with the regulation of multiple plant hormones at the level of synthesis, transport, or signaling (Weller et al 2015). Therefore, the impact of light on the plant growth is a complex phenomenon.…”