2. Sachin Kumar
21028
M.Sc. 1st year
Division of Seed Science and
Technology
ICAR-IARI, New Delhi
Male sterility induced by CHA SQ-1
in wheat plant
Credit seminar
4. Uses of MS
• For Hybrid seed development.
HYBRIDS?
SCH
DCH
TCH
5. CHEMICAL INDUCED MS
The chemicals that induce artificial and non genetic
male sterility in plants are called CHA.
The term CHA suggested by McRae in 1985 to
avoid confusion and multiplicity of terms such as.
Malesterilants , Androcides , Gametocyte, pollen
suppressants, pollenocides ,etc.
7. Why we are using CHA?
High performing female parents for F1 hybrid
It can use where Emasculation is difficult(specially in SPC)
Any line can be used as a female parents
No need of maintaining A, B and R-line
Choice of parents entirely flexible
CHA based F2 are fully fertile as compared to few sterile
hybrids in case of CMS or GMS.
Its also provide ideal material for study of reproductive
growth, Cytoplasmic Inheritance and Pollen
development.
10. Uses of CHA in wheat crop
Emasculation of each floret is difficult
Low seed multiplication per AP
Non availability of Effective MS system
Recent estimates of yield improvements associated
with heterosis in wheat range from 3.5 to 15%
(Longin et al., 2012).
Necessity of CHA in wheat?
11. Contd…
The earliest report of CHA use in wheat was MH
(Hoagland et al., 1953).
Recently, more than 40 applicable CHAs have been
reported for wheat (Singh et al., 2015b).
Out of these, some are found effective in inducing MS ,
such as RH0007, SC2053 and Genesis.
All these chemicals showed strong phytotoxic effects and
inadequate male sterility across a range of environments
and their commercial use was considered too risky.
12. SQ-1 The New CHA for Wheat:
• It is new pyridazine compound.
• It’s main ingredient is 4-chloroniline.
• Highly effective for utilization of heterosis.
• Very low phytotoxic and pollution.
• Can lead complete male sterility.
• No side effect on agronomical traits(Zhu et al. 2012,
2013).
13. Compared with existing CHA , SQ-1 is an
ideal chemical hybridization agent which
could induce male sterility by
Changing the cell microstructure
Triggering PCD of Tapetum and microspore
Striking the oxidative/antioxidative balance
Mitochondrial dysfunction
How SQ-1 induce male sterility in wheat plant
16. RESEARCH ARTICLE
Abnormal Development of Tapetum and Microspores
Induced by Chemical Hybridization Agent SQ-1 in
Wheat
Shuping Wang1, Gaisheng Zhang1*, Qilu Song1, Yingxin Zhang2, Zheng Li1, Jialin Guo1,
Na Niu1, Shoucai Ma1, Junwei Wang1
To investigate the CHA SQ-1 induced MS in wheat plant, and compared
morphological changes between normal anther and treated MS anther
Objective
17. Materials and methods
Chemical used-SQ-1@5kg/ha
Wheat variety-Xinong 1376
All plants are grown conventionally in wheat field
Spray of SQ-1@ stage 8.5 Feekes’ scale
Pollen morphology
Pollen fertility
Microspore development stage
TUNEL-assay
FDA staining
18. Comparison of Stamens And Pistils of Untreated And
CHA SQ-1 Treated Wheat plant
Td Eun Lun Bn Tn stage
UT
Tr
19. SEM Observations of untreated and SQ-1 treated
Anthers of wheat plant at trinucleate stage
Epidermis
Inner Epidermis
Ubisch bodies
Having sporopollenin and attached with
the peritapetal wall
20. Development of anther and microspore in untreated
and SQ-1 traeated wheat plant
Safranin stained
1% acetocarmine stained
UT
T
Safraninstained1%acetocarmine
24. Discussion
1. During the development of anther , tapetal cell
degradation and anther dehiscence recognized
features of PCD in male sterility
2. Discovered the accurate period of pollen abortion
at the early uninucleate stage.
3. The development pattern of tapetum and
microspore in SQ-1 treated plant.
25. Objective
To investigate effects of different treatment times of CHA SQ-1 used,
and detect morphological, biochemical and physiological responses of
wheat flag leaf
26. The average rate of MS induced by SQ-1
and AP seed set in different treatment
94
95
96
97
98
99
100
101
2 4 6 10 24
MS SEED SET AFTER AP
27. SEM of cuticle surface of flag leaf blades
UT 2h 4h 6h 10h 24h
Wax on surface
Guard cells
31. Discussion
1. CHA-SQ-1-treated flag leaf is responsible for MS
2. SQ-1 rapidly absorbed by flag leaves at 2h after
treatment and 100% MS were induced after 6h.
3. SQ-1 cause cellular oxidative stress in flag leaf
4. After 6h of treatment young flag leaf started to
return green mature leaf.
32. Mitochondrial Dysfunction Causes Oxidative Stress
and Tapetal Apoptosis in Chemical Hybridization
Reagent-Induced Male Sterility in Wheat
Shuping Wang1,2*†, Yingxin Zhang3†, Qilu Song1, Zhengwu Fang2, Zheng Chen1,
Yamin Zhang1, Lili Zhang1, Lin Zhang4, Na Niu1, Shoucai Ma1, Junwei Wang1,
Yaqin Yao5, Zanmin Hu3 and Gaisheng Zhang1*
ORIGINAL RESEARCH
published: 10 January 2018
doi: 10.3389/fpls.2017.02217
Objective
To investigate relationship between mitochondrial dysfunction
and CHA-induced male sterility in wheat plant
33. Materials and methods
Chemical used-SQ-1@5kg/ha
Wheat variety-Xinong 1376
All plants are grown conventionally in wheat field
Spray of SQ-1@ stage 8.5 Feekes’ scale
Mitochondrial protein analysis
COX and ATPase activity measurements
ROS measurement
Enzyme assays for SOD, CAT, POD and MnSOD
Respiratory activity measurements
pPCR Assay
41. Discussion
• Mitochondrial dysfunction i.e. Inhibited mtETC
reduce pollen grain production and cause MS.
• ROS in mt –mediated apoptosis in anther that
leads to tapetum cell degradation.
42. Conclusion
• Wheat flag leaves are the initial recipient tissue of
CHA-SQ-1 and responsible for MS.
• The 100% MS observed after 6h of treatment .
• After 6h of treatment young flag leaf started to
return green mature leaf.
• The main cause of PCD is oxidative stress in both
Anther and Flag leaves.
• Pollen abortion start from Eun stage of microspore
development.
• SQ-1 modifies the reproductive biology of wheat
,this ensure cross pollination.
43. Future prospective
• Further study require on gene regulatory
mechanisms underlying male sterility
involving wheat.
• How the flag leaf adjusts its defiance
mechanism against SQ-1 stress,
• Relationship between PCD and oxidative stress
under the abiotic stress are still unknown.