Hemoglobin regulation of plant embryogenesis and plant pathogen interaction

Hemoglobin LjGlb1-1 is involved in nodulation and regulates the level of nitric oxide in theLotus japonicus–Mesorhizobium lotisymbiosis

“…The NO levels in the roots of WT and mutant plants were compared because class 1 Hbs may modulate the NO concentration in vivo ( Hebelstrup et al , 2013 ; Wally et al , 2013 ). For this purpose, the NO-specific fluorescent dye DAF-FM DA was applied to the roots 3h after inoculation with M. loti and then incubated for 1h.…”

Overexpression of phytoglobin in barley alters both compatible and incompatible interactions with the mildew pathogen Blumeria graminis

“…()) were identified later in several species including barley ( Hordeum vulgare ; Hebelstrup et al ., ). An array of functions appears to be linked to phytoglobin and in most cases this involves regulation of NO turnover and signalling effects, in particular during stress situations such as diseases (Wally et al ., ). However, the understanding of phytoglobin function during pathogen infection is still rudimentary.…”

Protection of root apex meristem during stress responses

“…However, within the reproductive tissue, OsPgb1.5 expression could only be found in the lemma, while OsPgb1.3 was expressed in the palea. Cell and tissue specific localization of Pgbs was also documented in Arabidopsis 20,22 and maize. 24 In the same studies it was demonstrated that domains expressing Pgbs were generally depleted of NO while those suppressing Pgbs accumulated NO.…”

“…As NO scavengers, Pgbs have the capacity to interrupt the action of NO and manage plant developmental and stress responses in which NO is a component of the signal transduction pathway orchestrating hormone responses and PCD. 4,5,19,20,21,22 More importantly, the expression of Pgbs can be cell-specific, allowing cells adjacent to one another to respond differently to a given perturbation.…”

“…8 These unique molecules are present at different stages of plant development, such as embryogenesis, 20 seed germination, 33 de novo organogenesis, 34 root differentiation and flower development. 22 Induced by abiotic stress conditions such as hypoxia, cold and heat, Pgbs interfere with hormone signaling pathways actively and trigger a multitude of cellular phenotypes via the refinement of NO signaling. 9 The observation that there are as many as five Pgb genes, as well as a truncated form that codes for a protein that essentially performs the same chemical reactions, suggests that the protein can potentially be strategically expressed to switch on and off distinct NO-mediated functions in specific plant tissues.…”