Non-symbiotic haemoglobins—What's happening beyond nitric oxide scavenging?

Hill, Robert D.

doi:10.1093/aobpla/pls004

Cited by 139 publications

(125 citation statements)

References 117 publications

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“…This led to the suggestion that MPK6 may participate in maintaining poorly translated mRNAs during the stress so that they may be translated upon reoxygenation. Mitochondrial emission of NO also occurs under severe hypoxia (less than 1% oxygen) and was linked to signal transduction and metabolism (Hebelstrup et al, 2012;Hill, 2012). Hebelstrup et al (2012) showed that NO contributes to ethylene-dependent leaf hyponasty.…”

Section: Indirect Sensingmentioning

confidence: 99%

“…It has been known for a considerable time that the NO scavenger HB1 contributes to the regulation of low-oxygen gene regulation and metabolism during seed development and transient hypoxia in several species (Hill, 2012). Therefore, low-oxygentriggered NO production and HB1 scavenging may be involved in the regulation of group VII ERF turnover.…”

Section: Direct Oxygen Sensing Regulates the Turnover Of Transcriptiomentioning

confidence: 99%

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Waterproofing Crops: Effective Flooding Survival Strategies

2012

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Section: Indirect Sensingmentioning

confidence: 99%

Section: Direct Oxygen Sensing Regulates the Turnover Of Transcriptiomentioning

confidence: 99%

Waterproofing Crops: Effective Flooding Survival Strategies

2012

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“…NO is a hormone-like radical that modulates several aspects of the plant physiology, including plant immunity, seed germination, de-etiolation, apoptosis, stomata guard cells opening/closure and the rhizobia-legume symbiosis 111– 122 . Scavenging of NO is considered a function of plant Hbs 11, 123– 126 . During this process, oxygenated plant Hbs react with NO producing nitrate and oxidizing ferrous Hb to the ferric form.…”

Section: Postulated Functions For Rice Hemoglobinsmentioning

confidence: 99%

“…This process regenerates ferrous Hb which is able to bind NO in a cyclic pathway referred to as the Hb/NO cycle 126, 134 . The operation of this cycle appears to be involved in maintaining an active metabolism in the plant cells 11 . Rice Hb1 exhibits NO dioxygenase activity (k obs, NOD = 90 s -1 ) 135 thus a possible function of Hbs into the rice physiology is modulating levels of NO by scavenging NO.…”

Section: Postulated Functions For Rice Hemoglobinsmentioning

confidence: 99%

Rice (Oryza) hemoglobins

2014

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Hemoglobins (Hbs) corresponding to non-symbiotic (nsHb) and truncated (tHb) Hbs have been identified in rice ( Oryza). This review discusses the major findings from the current studies on rice Hbs. At the molecular level, a family of the nshb genes, consisting of hb1, hb2, hb3, hb4 and hb5, and a single copy of the thb gene exist in Oryza sativa var. indica and O. sativa var. japonica, Hb transcripts coexist in rice organs and Hb polypeptides exist in rice embryonic and vegetative organs and in the cytoplasm of differentiating cells. At the structural level, the crystal structure of rice Hb1 has been elucidated, and the structures of the other rice Hbs have been modeled. Kinetic analysis indicated that rice Hb1 and 2, and possibly rice Hb3 and 4, exhibit an extremely high affinity for O 2, whereas rice Hb5 and tHb possibly exhibit a low to moderate affinity for O 2. Based on the accumulated information on the properties of rice Hbs and data from the analysis of other plant and non-plant Hbs, it is likely that Hbs play a variety of roles in rice organs, including O 2-transport, O 2-sensing, NO-scavenging and redox-signaling. From an evolutionary perspective, an outline for the evolution of rice Hbs is available. Rice nshb and thb genes vertically evolved through different lineages, rice nsHbs evolved into clade I and clade II lineages and rice nshbs and thbs evolved under the effect of neutral selection. This review also reveals lacunae in our ability to completely understand rice Hbs. Primary lacunae are the absence of experimental information about the precise functions of rice Hbs, the properties of modeled rice Hbs and the cis-elements and trans-acting factors that regulate the expression of rice hb genes, and the partial understanding of the evolution of rice Hbs.

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“…17 Oxyhemoglobin reacts very rapidly with NO and regulating cellular NO levels is a more plausible function of these Hbs. 2 The Hb-mediated alterations of cellular NO interfere with hormone signaling as NO acts as a messenger in hormone synthesis and response. There are results of several published studies that could be interpreted in this fashion.…”

mentioning

confidence: 99%