Ethylene Inhibitors Restore Nodulation to <i>sym</i> 5 Mutants of <i>Pisum sativum</i> L. cv Sparkle

Fearn, Jeffrey C.; LaRue, Thomas A.

doi:10.1104/pp.96.1.239

Cited by 78 publications

(45 citation statements)

References 19 publications

(18 reference statements)

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“…Both low temperature and Ag+ increased nodulation of the mutant. These results are similar to those reported previously (3,4).…”

Section: Methodssupporting

confidence: 93%

“…In addition, in the mutant, infection threads are seldom associated with cortical cell divisions. Nodulation of the mutant is enhanced by cool root temperature (which may lower ethylene production) and by Ag+ (an inhibitor of ethylene action) (3,4). However, we still lack direct evidence implicating ethylene in the inhibition of nodule primordium formation.…”

Section: Ag+ Treatmentmentioning

confidence: 96%

“…The sym 5 mutants are temperature sensitive; in growth rooms, a few nodules consistently form at a cool root temperature (12°C), whereas nodules rarely develop at higher root temperatures (20-23°C) (3). At both temperatures, nodulation of the sym 5 mutants is enhanced if roots are treated with aminoethoxyvinylglycine or Ag+, which are inhibitors of ethylene formation or action, respectively (4). This suggests that, in the sym 5 mutants, some stage of nodule formation is oversensitive to ethylene.…”

mentioning

confidence: 99%

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Light Microscopy Study of Nodule Initiation in Pisum sativum L. cv Sparkle and in Its Low-Nodulating Mutant E2 (sym 5)

Guinel¹,

LaRue²

1991

Plant Physiol.

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We compared nodule initiation in lateral roots of Pisum sativum (L.) cv Sparkle and in a low-nodulating mutant E2 (sym 5). In Sparkle, about 25% of the infections terminated in the epidermis, a similar number stopped in the cortex, and 50% resulted in the formation of a nodule meristem or an emerged nodule. The mutant E2 (sym 5) was infected as often as was the parent, and it formed a normal infection thread. In the mutant, cell divisions rarely occurred in advance of the infection thread, and few nodule primordia were produced. Growing the mutant at a low root temperature or adding Ag+ to the substrate increased the number of cell divisions and nodule primordia. We conclude that, in the E2 line, the infection process is arrested in the cortex, at the stage of initial cell divisions before the establishment of a nodule primordium.Pisum sativum (L.) cv Sparkle forms many small nodules on its lateral roots, mostly within 2.5 cm of the primary root. Sparkle was mutagenized to induce symbiosis (sym) gene mutants defective in nodulation (8). Seven mutants at the sym 5 locus were independently selected as having few or no nodules (7,8). The sym 5 mutants are temperature sensitive; in growth rooms, a few nodules consistently form at a cool root temperature (12°C), whereas nodules rarely develop at higher root temperatures (20-23°C) (3). At both temperatures, nodulation of the sym 5 mutants is enhanced if roots are treated with aminoethoxyvinylglycine or Ag+, which are inhibitors of ethylene formation or action, respectively (4). This suggests that, in the sym 5 mutants, some stage of nodule formation is oversensitive to ethylene.Nodule development in peas has been described by a number of authors (10,14). Briefly, after root hair curling and infection thread formation, the infection thread branches in the outer cortex and grows toward the inner cortex. In the inner cortex, anticlinal cell divisions occur in advance of the thread and a nodule primordium is established. The infection thread branches grow into this center of dividing cells, releasing bacteria from the tips of the threads. A nodule meristem forms at one end of the nodule primordium, and eventually an infected nodule emerges from the root.In this study, we compared a mutant sym 5 line with its Because it was impractical to study the entire root, we conducted a census of the infection stages in two representative portions of lateral roots. MATERIALS AND METHODSSeeds of Pisum sativum (L.) cv Sparkle and of the mutant E2 (sym 5) were surface sterilized for 8 min with 5% (v/v) aqueous household bleach and rinsed several times with sterile distilled water. Seeds were planted individually in 3.5-x 20-cm conical pots (Ray Leach Conetainer Nursery, Canby, OR) filled with coarse vermiculite wetted with nutrient solution (3). The plants were subirrigated with nutrient solution and grown under high pressure sodium vapor and metal halide lamps (550 ,umol m-2 s-' PPFD) with a day/night cycle of 16/8 h. Roots were kept at a constant temperature of either 12 or 23...

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“…Both low temperature and Ag+ increased nodulation of the mutant. These results are similar to those reported previously (3,4).…”

Section: Methodssupporting

confidence: 93%

Section: Ag+ Treatmentmentioning

confidence: 96%

mentioning

confidence: 99%

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Light Microscopy Study of Nodule Initiation in Pisum sativum L. cv Sparkle and in Its Low-Nodulating Mutant E2 (sym 5)

Guinel¹,

LaRue²

1991

Plant Physiol.

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“…nigra ; Zaat et al, 1989) and soybean (Sugamuna et al, 1995 ;Ligero et al, 1999). Ethylene inhibitors significantly increased nodulation in alfalfa (Ligero et al, 1991 ;Caba et al, 1998) and in soybean (Ligero et al, 1999), even in the presence of inhibitory levels of nitrate, and restored nodulation in some pea nodulation mutants (Fearn & LaRue, 1991). It has also been suggested that endogenous ethylene provides positional information controlling the site where nodule primordia are formed (Heidstra et al, 1997).…”

Section: mentioning

confidence: 99%

“…Data on ethylene production or perception of such mutants are not known. Work by Fearn & LaRue (1991) has nonetheless shown that ethylene inhibitors partially restore nodulation to some of their pea nodulation (sym) mutants.…”

Section: mentioning

confidence: 99%

Differential sensitivity of nodulation to ethylene in soybean cv. Bragg and a supernodulating mutant

et al. 1999

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We previously found that the ethylene inhibitor Ag + could overcome the inhibitory effect of nitrate on nodulation of soybean (Glycine max) cv. Bragg. The same treatment increased nodulation quantitatively under non-inhibitory conditions, strongly suggesting involvement of ethylene in the control of nodulation in this species. Supernodulation mutants that lack internal autoregulation of nodulation, however, had biosynthesis capacity similar to the wild type. In the present work, the effects of ethylene on nodulation of ' Bragg ' and two separate, but allelic, supernodulating mutants (nts382 and nts1007) were compared. The nodulation process appeared much more sensitive than plant growth and development to ethylene, which reduced the number of nodules per plant, but nearly twofold more in the wild type than in the supernodulation mutants. The cause-effect relationship is established by the counteracting effect of Ag + and the fact that the stronger the inhibition by ethylene, the higher the recovery of nodulation ability with the ethylene antagonist. This higher tolerance of or lower sensitivity to ethylene in nts382 persists even under low inoculum dose, where nodule number and mass could be decreased to wild-type levels. Differences between the mutant and the wild type in the triple response test do not appear to support differences in ethylene perception on a whole-plant basis. The results suggest that sensitivity of nodulation to ethylene might have been affected in supernodulation mutants.

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Use of Pea (Pisum sativum L.) Mutants Impaired in Nodulation and Root Formation to Study the Role of Phytohormones in Nodule Development

Pavlova

Tsyganov

Кравченко

et al.

Nitrogen Fixation: From Molecules to Crop Productivity

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Ethylene Inhibitors Restore Nodulation to sym 5 Mutants of Pisum sativum L. cv Sparkle

Cited by 78 publications

References 19 publications

Light Microscopy Study of Nodule Initiation in Pisum sativum L. cv Sparkle and in Its Low-Nodulating Mutant E2 (sym 5)

Light Microscopy Study of Nodule Initiation in Pisum sativum L. cv Sparkle and in Its Low-Nodulating Mutant E2 (sym 5)

Differential sensitivity of nodulation to ethylene in soybean cv. Bragg and a supernodulating mutant

Use of Pea (Pisum sativum L.) Mutants Impaired in Nodulation and Root Formation to Study the Role of Phytohormones in Nodule Development

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